Updated on 2021/10/20

写真a

 
HISHIKAWA, Akiyoshi
 
Organization
Research Center for Materials Science Professor
Graduate School
Graduate School of Science
Title
Professor
Contact information
メールアドレス

Degree 1

  1. Doc. Eng. ( 1994.3   Kyoto University ) 

Research Areas 2

  1. Nanotechnology/Materials / Fundamental physical chemistry

  2. Natural Science / Semiconductors, optical properties of condensed matter and atomic physics

Research History 6

  1. Nagoya University   Research Center for Materials Science   Professor

    2015.4

  2. Nagoya University   RCMS   Professor

    2015.4

  3. Nagoya University   Graduate School of Science   Professor

    2010.4 - 2015.3

  4. Institute for Molecular Science   Associate professor

    2003.4 - 2010.3

  5. University of Tokyo   Graduate School of Science   Assistant Professor

    1999.10 - 2003.3

  6. University of Tokyo   Graduate School of Science   Lecturer

    1998.2 - 1999.9

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Education 4

  1. Kyoto University   Graduate School, Division of Engineering   Department of Engineering Science

    1991.4 - 1994.3

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    Country: Japan

  2. Kyoto University   Gratduate School of Engineering   Department of Engineering Science

    1989.4 - 1991.3

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    Country: Japan

  3. Kyoto University   School of Engineering   Department of Endineering Science

    1985.4 - 1989.3

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    Country: Japan

  4. Kyoto University   Graduate School of Engineering   Department of Engineering Science

    1991.4 - 1994.3

Professional Memberships 6

  1. 分子科学会

  2. 日本化学会

  3. 日本物理学会

  4. 強光子場科学研究懇談会

  5. 原子衝突学会

  6. 日本分光学会

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Awards 1

  1. 第35回日本化学会学術賞

    2018.3   日本化学会  

    菱川 明栄

 

Papers 125

  1. Time-resolved shot-by-shot photoelectron spectroscopy of autoionizing Xe+ states by EUV–free-electron-laser and near-IR laser pulses Reviewed

    Mizuho Fushitani, Yoshitaka Kawabe, Hikaru Fujise, Makoto Yamada, Hiroka Hasegawa, Shigeki Owada, Tadashi Togashi, Kyo Nakajima, Makina Yabashi, Akitaka Matsuda, Yasumasa Hikosaka, Akiyoshi Hishikawa

    Physical Review A   Vol. 104 ( 2 )   2021.8

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/PhysRevA.104.023102

    Web of Science

    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevA.104.023102/fulltext

  2. Time-resolved photoelectron imaging of complex resonances in molecular nitrogen Reviewed International coauthorship

    Mizuho Fushitani, Stephen T. Pratt, Daehyun You, Shu Saito, Yu Luo, Kiyoshi Ueda, Hikaru Fujise, Akiyoshi Hishikawa, Heide Ibrahim, François Légaré, Per Johnsson, Jasper Peschel, Emma R. Simpson, Anna Olofsson, Johan Mauritsson, Paolo Antonio Carpeggiani, Praveen Kumar Maroju, Matteo Moioli, Dominik Ertel, Ronak Shah, Giuseppe Sansone, Tamás Csizmadia, Mathieu Dumergue, N. G. Harshitha, Sergei Kühn, Carlo Callegari, Oksana Plekan, Michele Di Fraia, Miltcho B. Danailov, Alexander Demidovich, Luca Giannessi, Lorenzo Raimondi, Marco Zangrando, Giovanni De Ninno, Primož Rebernik Ribič, Kevin C. Prince

    The Journal of Chemical Physics   Vol. 154 ( 14 ) page: 144305 - 144305   2021.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AIP Publishing  

    DOI: 10.1063/5.0046577

    Web of Science

    Other Link: https://aip.scitation.org/doi/pdf/10.1063/5.0046577

  3. Capturing roaming molecular fragments in real time Reviewed International coauthorship International journal

    Tomoyuki Endo, Simon P. Neville, Vincent Wanie, Samuel Beaulieu, Chen Qu, Jude Deschamps, Philippe Lassonde, Bruno E. Schmidt, Hikaru Fujise, Mizuho Fushitani, Akiyoshi Hishikawa, Paul L. Houston, Joel M. Bowman, Michael S. Schuurman, François Lé garé, Heide Ibrahim

    Science   Vol. 370 ( 6520 ) page: 1072 - +   2020.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Association for the Advancement of Science ({AAAS})  

    <jats:p>Since the discovery of roaming as an alternative molecular dissociation pathway in formaldehyde (H<jats:sub>2</jats:sub>CO), it has been indirectly observed in numerous molecules. The phenomenon describes a frustrated dissociation with fragments roaming at relatively large interatomic distances rather than following conventional transition-state dissociation; incipient radicals from the parent molecule self-react to form molecular products. Roaming has been identified spectroscopically through static product channel–resolved measurements, but not in real-time observations of the roaming fragment itself. Using time-resolved Coulomb explosion imaging (CEI), we directly imaged individual “roamers” on ultrafast time scales in the prototypical formaldehyde dissociation reaction. Using high-level first-principles simulations of all critical experimental steps, distinctive roaming signatures were identified. These were rendered observable by extracting rare stochastic events out of an overwhelming background using the highly sensitive CEI method.</jats:p>

    DOI: 10.1126/science.abc2960

    Web of Science

  4. Ultrafast Reaction Imaging and Control by Ultrashort Intense Laser Pulses Invited Reviewed

    Akiyoshi Hishikawa, Akitaka Matsuda, Mizuho Fushitani

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   Vol. 93 ( 11 ) page: 1293 - 1304   2020.11

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:CHEMICAL SOC JAPAN  

    Molecules irradiated with intense laser pulses (field intensity similar to 10(15) W/cm(2)) exhibit a variety of characteristic processes, such as tunneling ionization, electron rescattering, high-order harmonics generation and Coulomb explosion, that cannot be seen in a weak light field. These features have attracted attention in the last decades as they provide unique approaches to visualize and manipulate ultrafast dynamics of atoms and molecules. Here we discuss molecular processes in intense laser fields, with focuses on the applications to ultrafast imaging and control of reaction dynamics.

    DOI: 10.1246/bcsj.20200158

    Web of Science

  5. Characterization of soft X-ray FEL pulse duration with two-color photoelectron spectroscopy Reviewed

    Shigeki Owada, Mizuho Fushitani, Akitaka Matsuda, Hikaru Fujise, Yuuma Sasaki, Yasumasa Hikosaka, Akiyoshi Hishikawa, Makina Yabashi

    JOURNAL OF SYNCHROTRON RADIATION   Vol. 27 ( 5 ) page: 1362 - 1365   2020.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:INT UNION CRYSTALLOGRAPHY  

    The pulse duration of soft X-ray free-electron laser (FEL) pulses of SACLA BL1 (0.2-0.3 nC per bunch, 0.5-0.8 MeV) were characterized by photoelectron sideband measurements. The intensity of the He 1 s(-1) photoelectron sidebands generated by a near-infrared femtosecond laser was measured as a function of the time delay between the two pulses using an arrival time monitor. From the width of the cross-correlation trace thus derived, the FEL pulse duration was evaluated to be 28 +/- 5 fs full width at half-maximum in the photon energy range between 40 eV and 120 eV.

    DOI: 10.1107/S1600577520008516

    Web of Science

  6. Multielectron-Ion Coincidence Spectroscopy of Xe in Extreme Ultraviolet Laser Fields: Nonlinear Multiple Ionization via Double Core-Hole States Reviewed International journal

    M. Fushitani, Y. Sasaki, A. Matsuda, H. Fujise, Y. Kawabe, K. Hashigaya, S. Owada, T. Togashi, K. Nakajima, M. Yabashi, Y. Hikosaka, A. Hishikawa

    Physical Review Letters   Vol. 124 ( 19 )   2020.5

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society ({APS})  

    DOI: 10.1103/PhysRevLett.124.193201

    Web of Science

  7. Angle dependence of dissociative tunneling ionization of NO in asymmetric two-color intense laser fields Reviewed

    Tomoyuki Endo, Hikaru Fujise, Hiroka Hasegawa, Akitaka Matsuda, Mizuho Fushitani, Oleg I. Tolstikhin, Toru Morishita, Akiyoshi Hishikawa

    Physical Review A   Vol. 100 ( 5 ) page: 053422   2019.11

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    Authorship:Last author, Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    © 2019 American Physical Society. Dissociative tunneling ionization of nitric oxide (NO) in linearly polarized phase-locked two-color femtosecond intense laser fields (45 fs, λ=800 and 400 nm, total field intensity I=1×1014W/cm2) has been studied by three-dimensional ion momentum imaging. The N+ fragment produced by the dissociative ionization, NO→NO++e-→N++O+e-, exhibits a butterflylike momentum distribution peaked at finite angles with respect to the laser polarization direction. In addition, a clear dependence on the relative phase between the two laser fields is observed, showing that the tunneling ionization occurs efficiently when the electric field points from N to O. For the highest kinetic energy component, the observed orientation dependence is well explained with theoretical calculations by the weak-field asymptotic theory for the 2πhighest occupied molecular orbital (HOMO). On the other hand, the peak angle shifts toward the laser polarization direction as the kinetic energy decreases, indicating that pathways other than direct ionization from the HOMO contribute to the dissociative ionization.

    DOI: 10.1103/PhysRevA.100.053422

    Web of Science

    Scopus

  8. Probing Rydberg-Rydberg interactions in N<inf>2</inf> by ultrafast EUV-NIR photoelectron spectroscopy Reviewed International coauthorship

    Fushitani, M., Toida, Y., Légaré, F., Hishikawa, A.

    Optics Express   Vol. 27 ( 14 ) page: 19702 - 19711   2019.7

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    Authorship:Last author, Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1364/OE.27.019702

    Web of Science

    Scopus

  9. Coincidence momentum imaging of four- and three-body Coulomb explosion of formaldehyde in ultrashort intense laser fields Reviewed International coauthorship

    Chien-Ming Tseng, Mizuho Fushitani, Akitaka Matsuda, Akiyoshi Hishikawa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 228   page: 25 - 30   2018.10

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Ion-coincidence momentum imaging of Coulomb explosion of formaldehyde (H2CO) in femtosecond intense laser fields (800 nm, 1.3 x 10(15) W/cm(2)) is performed with two different laser pulse durations (7 fs and 35 fs). In the 7-fs laser fields, the full fragmentation pathway from H2CO4+ -> H+ + H+ + C+ + O+ is identified. The angles between the fragment momenta are well reproduced by a simple Coulomb explosion model from the geometry of neutral formaldehyde, showing that the molecular structure is virtually frozen along the bending coordinates during the multiple ionization. Three-body Coulomb explosion pathways from triply charged states, H2CO3+ -> H+ + H+ + C+ + O+, are observed in both the 7-fs and 35-fs laser fields. Significant changes in the momentum angle distribution and asymmetric energy partitioning between two H+ ions are observed in the 35-fs case, which are attributed to structural deformation prior to the Coulomb explosion in the longer pulse.

    DOI: 10.1016/j.elspec.2018.07.001

    Web of Science

  10. Femtosecond laser filamentation in gaseous ethylene: Formation of hydrogenated amorphous carbon Reviewed

    A. Matsuda, T. Hayashi, R. Kitaura, A. Hishikawa

    Chem. Lett.   Vol. 46   page: 1426-1429   2017.7

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1246/cl.170613

  11. Selective bond breaking of CO2 in phase-locked two-color intense laser fields: laser field intensity dependence Reviewed

    Tomoyuki Endo, Hikaru Fujise, Yuuna Kawachi, Ayaka Ishihara, Akitaka Matsuda, Mizuho Fushitani, Hirohiko Kono, Akiyoshi Hishikawa

    PHYSICAL CHEMISTRY CHEMICAL PHYSICS   Vol. 19 ( 5 ) page: 3550 - 3556   2017.2

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:ROYAL SOC CHEMISTRY  

    Selective bond breaking of CO2 in phase-locked omega-2 omega two-color intense laser fields (lambda = 800 nm and 400 nm, total field intensity l similar to 10(14) W cm(-2)) has been investigated by coincidence momentum imaging. The CO+ and O+ fragment ions produced by two-body Coulomb explosion, CO22+ -&gt; CO+ + O+, exhibit asymmetric distributions along the laser polarization direction, showing that one of the two equivalent C-O bonds is selectively broken by the laser fields. At a field intensity higher than 2 x 10(14) W cm(-2), the largest fragment asymmetry is observed when the relative phase phi between the omega and 2 omega laser fields is similar to 0 and pi. On the other hand, an increase of the asymmetry and a shift of the phase providing the largest asymmetry are observed at lower field intensities. The selective bond breaking and its dependence on the laser field intensity are discussed in terms of a mechanism involving deformation of the potential energy surfaces and electron recollision in intense laser fields.

    DOI: 10.1039/c6cp07471e

    Web of Science

  12. Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics Reviewed

    Fushitani, M., Hishikawa, A.

    Structural Dynamics   Vol. 3 ( 6 ) page: 062602   2016.11

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4964775

    Web of Science

    Scopus

  13. Imaging Electronic Excitation of NO by Ultrafast Laser Tunneling Ionization Reviewed

    Tomoyuki Endo, Akitaka Matsuda, Mizuho Fushitani, Tomokazu Yasuike, Oleg I. Tolstikhin, Toru Morishita, Akiyoshi Hishikawa

    PHYSICAL REVIEW LETTERS   Vol. 116 ( 16 ) page: 163002   2016.4

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    Tunneling-ionization imaging of photoexcitation of NO has been demonstrated by using few-cycle near-infrared intense laser pulses (8 fs, 800 nm, 1.1 x 10(14) W/cm(2)). The ion image of N+ fragment ions produced by dissociative ionization of NO in the ground state, NO (X-2 Pi; 2 pi) -&gt; NO+ + e(-) -&gt; N+ + O + e(-), exhibits a characteristic momentum distribution peaked at 45 degrees with respect to the laser polarization direction. On the other hand, a broad distribution centered at similar to 0 degrees appears when the A(2)Sigma(+) (3s sigma) excited state is prepared as the initial state by deep-UV photoexcitation. The observed angular distributions are in good agreement with the corresponding theoretical tunneling ionization yields, showing that the fragment anisotropy reflects changes of the highest-occupied molecular orbital by photoexcitation.

    DOI: 10.1103/PhysRevLett.116.163002

    Web of Science

  14. Photoelectron sidebands induced by a chirped laser field for shot-by-shot temporal characterization of FEL pulses Reviewed

    Chien-Nan Liu, Toru Morishita, Mizuho Fushitani, Akiyoshi Hishikawa

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 49 ( 3 ) page: 034005   2016.2

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    Authorship:Last author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We theoretically investigate the laser-assisted photoionization of He by an extreme ultra violet (XUV) pulse in the presence of a linearly chirped intense laser pulse by solving the time-dependent Schrodinger equation within the single-active-electron approximation. Analysis based on the time-dependent perturbation theory is also carried out to provide more physical insights. A new scheme is shown to be capable of extracting the arrival time of an XUV free-electron laser (FEL) pulse relative to an external laser pulse as well as the XUV pulse duration from the photoelectron sidebands resulting from XUV ionization in the presence of a chirped laser pulse. This scheme is independent of the energy fluctuation and the timing jittering of the FEL pulse. Therefore it can be implemented in a non-invasive way to characterize FEL pulses on a shot-by-shot basis in time-resolved spectroscopy.

    DOI: 10.1088/0953-4075/49/3/034005

    Web of Science

  15. Coincidence momentum imaging of asymmetric Coulomb explosion of CO2 in phase-locked two-color intense laser fields Reviewed

    Tomoyuki Endo, Hikaru Fujise, Akitaka Matsuda, Mizuho Fushitani, Hirohiko Kono, Akiyoshi Hishikawa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 207   page: 50 - 54   2016.2

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Coulomb explosion of CO2, CO2 -&gt; CO2+2 + 2e(-) -&gt; CO+ + O +2e(-), in phase-locked two-color ultrashort intense laser fields (800 nm and 400 nm, similar to 10(14) W/cm(2)) has been investigated by coincidence momentum imaging. The momentum images of the O+ and CO+ fragments show asymmetric distributions along the laser polarization direction depending on the relative phase of the two-color laser fields. The fragment asymmetry becomes most prominent (similar to 4%) at the relative phases providing the largest asymmetry of the electric field amplitude, with the O+ fragments preferentially ejected to the stronger field side. The mechanism of the asymmetric bond breaking of the two equivalent C-O bonds is discussed in terms of the nuclear dynamics in CO22+. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2015.12.010

    Web of Science

  16. Femtosecond two-photon Rabi oscillations in excited He driven by ultrashort intense laser fields Reviewed

    M. Fushitani, C. -N. Liu, A. Matsuda, T. Endo, Y. Toida, M. Nagasono, T. Togashi, M. Yabashi, T. Ishikawa, Y. Hikosaka, T. Morishita, A. Hishikawa

    NATURE PHOTONICS   Vol. 10 ( 2 ) page: 102 - +   2016.2

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    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

    Coherent light-matter interaction provides powerful methods for manipulating quantum systems(1-3). Rabi oscillation is one such process. As it enables complete population transfer to a target state, it is thus routinely exploited in a variety of applications in photonics, notably quantum information processing(4,5). The extension of coherent control techniques to the multiphoton regime offers wider applicability, and access to highly excited or dipole-forbidden transition states. However, the multiphoton Rabi process is often disrupted by other competing nonlinear effects such as the a.c. Stark shift, especially at the high laser-field intensities necessary to achieve ultrafast Rabi oscillations(6). Here we demonstrate a new route to drive two-photon Rabi oscillations on timescales as short as tens of femtoseconds, by utilizing the strong-field phenomenon known as Freeman resonance(7). The scenario is not specific to atomic helium as investigated in the present study, but broadly applicable to other systems, thus opening new prospects for the ultrafast manipulation of Rydberg states(8).

    DOI: 10.1038/NPHOTON.2015.228

    Web of Science

  17. Correlation between Photoeletron and Photoion in Ultrafast Multichannel Photoionization of Ar Reviewed

    R. Itakura, M. Fushitani, A. Hishikawa, T. Sako

    INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2015 (ICCMSE 2015)   Vol. 1702   2015

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    Publishing type:Research paper (international conference proceedings)   Publisher:AMER INST PHYSICS  

    We theoretically investigate coherent dynamics of ions created through ultrafast multichannel photoionization from a viewpoint of photoelectron-photoion correlation. The model calculation on single-photon ionization of Ar reveals that the coherent hole dynamics in Ar+ associated with a superposition of the spin-orbit states P-2(J) (J = 3/2 and 1/2) can be identified by monitoring only the photoion created by a Fourier-transform limited extreme ultraviolet (EUV) pulse with the 9-fs pulse duration, while the coherence is lost by a chirped EUV pulse. It is demonstrated that by coincidence detection of the photoelectron and photoion the coherent hole dynamics can be extracted even in the case of ionization by a chirped EUV pulse with the sufficiently wide bandwidth.

    DOI: 10.1063/1.4938829

    Web of Science

  18. Ion-Coincidence Momentum Imaging of Three-Body Coulomb Explosion of Formaldehyde in Ultrashort Intense Laser Fields Reviewed

    M. Fushitani, C-M. Tseng, A. Matsuda, A. Hishikawa

    INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2015 (ICCMSE 2015)   Vol. 1702   2015

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    Publishing type:Research paper (international conference proceedings)   Publisher:AMER INST PHYSICS  

    Three-body Coulomb explosion of formaldehyde (H2CO) in intense 7- and 35-fs laser fields (1.3 x 10(15) W/cm(2)) has been investigated by using ion-coincidence momentum imaging technique. Two types of explosion pathways from the triply charged state, H2CO3+ -&gt; (i) H+ + H+ + CO+ and (ii) H+ + CH+ + O+, have been identified. It is shown from the momentum correlation of the fragment ions of pathway (i), that the geometrical structure of the molecule is essentially frozen along the H-C-H bending coordinate for the 7-fs case. On the other hand, for a longer pulse duration (35 fs), structural deformation along the C-H stretching and H-C-H bending coordinates is identified, which is ascribed to the nuclear dynamics in the dication states populated within the laser pulse duration.

    DOI: 10.1063/1.4938821

    Web of Science

  19. Fragment anisotropy on dissociative ionization of NO in two-color intense laser fields Reviewed

    Tomoyuki Endo, Ayaka Ishihara, Akitaka Matsuda, Mizuho Fushitani, Akiyoshi Hishikawa

    XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12   Vol. 635   2015

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    Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    Dissociative-ionization of NO, NO -&gt; NO+ + e(-) -&gt; N+ + O + e(-), in omega-2 omega two-color phase-controlled intense laser fields was investigated by three-dimensional ion momentum imaging. The moment Urn image of the N+ ion exhibited anisotropic distributions peaked at 35 degrees against the laser polarization, which show clear left-right asymmetry depending on the omega-2 omega relative phase. The present study demonstrates that the molecular orbital can be retrieved by distinguishing the difference between the N and O side from the fragment anisotropy by intense laser pulses.

    DOI: 10.1088/1742-6596/635/11/112027

    Web of Science

  20. Determination of Absolute Cross-Sections of Nonresonant EUV-UV Two-Color Two-Photon Ionization of He Reviewed

    M. Fushitani, Y. Hikosaka, A. Matsuda, T. Endo, E. Shigemasa, M. Nagasono, T. Sato, T. Togashi, M. Yabashi, T. Ishikawa, A. Hishikawa

    ULTRAFAST PHENOMENA XIX   Vol. 162   page: 109 - 112   2015

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    Publishing type:Research paper (international conference proceedings)   Publisher:SPRINGER-VERLAG BERLIN  

    Single-shot photoelectron spectroscopy was performed for nonresonant EUV-UV two-color two-photon ionization of He. From data analysis on the shot-by-shot basis, the absolute cross-section was determined to be sigma((2))(59.7 nm, 268 nm) = 4.1(6) x 10(-52) cm(4) s.

    DOI: 10.1007/978-3-319-13242-6_26

    Web of Science

  21. Time-Resolved Coulomb Explosion Imaging of Ultrafast Fragmentation of CS2 in Highly Charged States Reviewed

    Akitaka Matsuda, Eiji J. Takahashi, Akiyoshi Hishikawa

    ULTRAFAST PHENOMENA XIX   Vol. 162   page: 168 - 171   2015

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    Publishing type:Research paper (international conference proceedings)   Publisher:SPRINGER-VERLAG BERLIN  

    Time-resolved three-body Coulomb explosion imaging of dissociating CS2 in few-cycle intense laser fields (9 fs, 4 x 10(15) W/cm(2)) is performed. It is revealed that the ultrafast fragmentation dynamics of CS2 in highly charged states proceed in a different timescale depending on the charge state.

    DOI: 10.1007/978-3-319-13242-6_40

    Web of Science

  22. Ultrafast two-photon Rabi oscillations in excited He driven by femtosecond intense laser fields Reviewed

    A. Hishikawa, M. Fushitani, C. N. Liu, A. Matsuda, T. Endo, Y. Toida, Y. Hikosaka, T. Morishita

    XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12   Vol. 635   2015

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    Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    We demonstrate ultrafast multiphoton coherent excitation in near-infrared intense laser fields (&lt;= 10 TW/cm(2)) using excited helium in the 1s2p (P-1) state as the target. Strong two-photon coupling between the 2p state and the 5f and 6f Rydberg states drives ultrafast Rabi oscillations in tens of femtosecond. Theoretical calculations solving the time-dependent Schrodinger equation were carried out to elucidate the strong field effects.

    DOI: 10.1088/1742-6596/635/9/092082

    Web of Science

  23. Five-photon sequential double ionization of He in intense extreme-ultraviolet free-electron laser fields Reviewed

    Y. Hikosaka, M. Fushitani, A. Matsuda, T. Endo, Y. Toida, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, M. Yabashi, T. Ishikawa, A. Hishikawa

    PHYSICAL REVIEW A   Vol. 90 ( 5 ) page: 053403   2014.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    A multiphoton ionization process of He in intense extreme ultraviolet free-electron laser fields is investigated in a photon energy range of hv = 20.1-20.8 eV using shot-by-shot photoelectron spectroscopy. A photoelectron peak resulting from sequential double ionization of He due to five-photon absorption is observed around hv = 20.4. Shot-by-shot analysis of photoelectron spectra shows that two-photon resonance to the He+(2s S-2) state from the He+ ground state is responsible for the substantial enhancement of five-photon double ionization. Effective cross sections for two-photon absorption between the 1s and 2s states of He+ and for one-photon absorption from the He+ 2s state are obtained.

    DOI: 10.1103/PhysRevA.90.053403

    Web of Science

  24. Photoelectron-photoion correlation in ultrafast multichannel photoionization of Ar Reviewed

    R. Itakura, M. Fushitani, A. Hishikawa, T. Sako

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 47 ( 19 ) page: 195602   2014.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    Ultrafast multichannel single-photon ionization of Ar is investigated theoretically by a model calculation incorporating correlation between the photoelectron and photoion. It is shown that the coherent hole dynamics in Ar+ associated with a superposition of the spin-orbit states can be observed by using a Fourier-transform limited laser pulse for ionization, while the coherence is degraded or lost by chirped a laser pulse. We demonstrate that the coherent hole dynamics can be retrieved even in the case of ionization by a chirped laser pulse, by labeling the photoion dynamics with the counterpart photoelectron energy.

    DOI: 10.1088/0953-4075/47/19/195602

    Web of Science

  25. Time-resolved laser Coulomb explosion imaging using few-cycle intense laser pulses: Application to exploding CS2 in highly charged states Reviewed

    Akitaka Matsuda, Eiji J. Takahashi, Akiyoshi Hishikawa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 195   page: 327 - 331   2014.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER  

    Ion-coincidence momentum imaging of three-body Coulomb explosion of CS2, CS2z+ -> Sp+ + Cq+ + Sr+ (z = p + q + r), in few-cycle intense laser fields (9 fs, similar to 10(15) W/cm(2)) is presented. It is shown that the momentum distributions of fragment ions produced from CS210+ are well reproduced by a classical explosion model incorporating the coordinate and momentum distributions of the initial ground vibrational state of CS2. On the other hand, a significant deviation is observed for CS23+ due to the non-Coulombic character of the potential energy surfaces. Coulomb explosion imaging is applied to real-time probing of Coulomb exploding CS2 in highly charged states, using a pair of intense few-cycle laser pulses. It is shown that the explosion proceeds in a different time scale depending on the charge state, mostly along the linear geometry during the bond-breaking of the two C S bonds. (C) 2013 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2013.12.011

    Web of Science

  26. Preface Reviewed

    Hiroshi Daimon, Akiyoshi Hishikawa, Catalin Miron

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 195   page: 285 - 286   2014.8

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    Publisher:ELSEVIER SCIENCE BV  

    DOI: 10.1016/j.elspec.2014.07.013

    Web of Science

  27. Special issue on ultrafast electron and molecular dynamics Preface Reviewed

    Fernando Martin, Akiyoshi Hishikawa, Marc Vrakking

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 47 ( 12 )   2014.6

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    Publisher:IOP PUBLISHING LTD  

    DOI: 10.1088/0953-4075/47/12/120201

    Web of Science

  28. Dissociative ionization of NO in few-cycle intense laser fields : Effects of pi-sigma electronic transition Reviewed

    Tomoyuki Endo, Mizuho Fushitani, Akitaka Matsuda, Akiyoshi Hishikawa

    XXVIII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC)   Vol. 488   2014

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    Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    Dissociative ionization (DI) of NO in few-cycle intense laser fields was investigated by using the 3D momentum imaging method. It was found that the symmetry change in the outermost occupied molecular orbital upon the pi - sigma electronic transition is clearly reflected in the spatial anisotropy of the fragment ion, N+.

    DOI: 10.1088/1742-6596/488/3/032025

    Web of Science

  29. Resolving the enhanced nonlinear double excitation of helium in intense ultra-short extreme-ultraviolet pulses Reviewed

    Chien-Nan Liu, Akiyoshi Hishikawa, Toru Morishita

    XXVIII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC)   Vol. 488   2014

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    Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    We present a theoretical study for multiphoton double excitation of He atoms exposed to an intense ultrashort extreme-ultraviolet (EUV) pulse, where the photon energy coincides with the transition energy from the ground state to a Rydberg state. We identify the mechanism of the enhanced three-photon absorption probability as observed in the experiment.

    DOI: 10.1088/1742-6596/488/3/032047

    Web of Science

  30. Two-photon rabi oscillations of excited he atoms in ultrafast strong laser field ionization Reviewed

    Fushitani M, Liu C.-N, Matsuda A, Endo T, Toida Y, Hikosaka Y, Nagasono M, Togashi T, Yabashi M, Ishikawa T, Morishita T, Hishikawa A

    Optics InfoBase Conference Papers     2014

  31. Nonresonant EUV-UV two-color two-photon ionization of He studied by single-shot photoelectron spectroscopy Reviewed

    M. Fushitani, Y. Hikosaka, A. Matsuda, T. Endo, E. Shigemasa, M. Nagasono, T. Sato, T. Togashi, M. Yabashi, T. Ishikawa, A. Hishikawa

    PHYSICAL REVIEW A   Vol. 88 ( 6 ) page: 063422   2013.12

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    Single-shot photoelectron spectroscopy of nonresonant two-color two-photon ionization of He has been carried out using an intense free-electron laser (FEL) at 59.7 nm and a femtosecond UV laser at 268 nm. By shot-by-shot analysis of photoelectron spectra, the cross section for nonresonant two-color ionization of He is determined to be sigma((2)) = 4.1(6) x 10(-52) cm(4) s. The cross-correlation trace derived from the nonresonant signals shows that the temporal resolution of the system is 0.36(3) ps, which is mainly governed by the timing jitter between the FEL and UV laser pulses.

    DOI: 10.1103/PhysRevA.88.063422

    Web of Science

  32. Compact XFEL and AMO sciences: SACLA and SCSS Reviewed

    M. Yabashi, H. Tanaka, T. Tanaka, H. Tomizawa, T. Togashi, M. Nagasono, T. Ishikawa, J. R. Harries, Y. Hikosaka, A. Hishikawa, K. Nagaya, N. Saito, E. Shigemasa, K. Yamanouchi, K. Ueda

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 46 ( 16 ) page: 164001   2013.8

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    The concept, design and performance of Japan's compact free-electron laser (FEL) facilities, the SPring-8 Compact SASE Source test accelerator (SCSS) and SPring-8 Angstrom Compact free electron LAser (SACLA), and their applications in mainly atomic, molecular and optical science are reviewed. At SCSS, intense, ultrafast FEL pulses at extreme ultraviolet (EUV) wavelengths have been utilized for investigating various multi-photon processes in atoms, molecules and clusters by means of ion and electron spectroscopy. The quantum optical effect superfluorescence has been observed with EUV excitation. A pump-probe technique combining FEL pulses with near infrared laser pulses has been realized to study the ultrafast dynamics of atoms, molecules and clusters in the sub-picosecond regime. At SACLA, deep inner-shell multi-photon ionization by intense x-ray FEL pulses has been investigated. The development of seeded FEL sources for producing transversely and temporally coherent light, as well as the expected impact on advanced science are discussed.

    DOI: 10.1088/0953-4075/46/16/164001

    Web of Science

  33. Resonances in three-photon double ionization of Ar in intense extreme ultraviolet free-electron laser fields studied by shot-by-shot photoelectron spectroscopy Reviewed

    Y. Hikosaka, M. Fushitani, A. Matsuda, T. Endo, Y. Toida, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, M. Yabashi, T. Ishikawa and A. Hishikawa

    Phys. Rev. A   Vol. 88 ( 023421 ) page: 023421   2013.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI: 10.1103/PhysRevA.88.023421]

  34. Resonances in three-photon double ionization of Ar in intense extreme-ultraviolet free-electron laser fields studied by shot-by-shot photoelectron spectroscopy Reviewed

    Y. Hikosaka, M. Fushitani, A. Matsuda, T. Endo, Y. Toida, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, M. Yabashi, T. Ishikawa, A. Hishikawa

    PHYSICAL REVIEW A   Vol. 88 ( 2 )   2013.8

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    Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    Shot-by-shot photoelectron spectroscopy has been performed to study the three-photon double ionization of Ar in intense extreme-ultraviolet free-electron laser fields over a photon energy range of 19.6-22.0 eV. It is found that the double ionization to Ar2+ 3p(-2) proceeds sequentially via the formation of singly charged Ar+ 3p(-1) states and is enhanced around photon energies of 20.5 and 21.5 eV. Two types of resonance are identified in the two-photon ionization of the Ar+ 3p(-1) states: (i) resonances to intermediate states at the one-photon energy level and (ii) those to autoionizing states above the Ar2+ ionization threshold.

    DOI: 10.1103/PhysRevA.88.023421

    Web of Science

  35. Time-resolved four-body coulomb explosion imaging of correlated dynamics of hydrogen atoms in acetylene dication Reviewed

    A. Matsuda, M. Fushitani, E. J. Takahashi, A. Hishikawa

    EPJ Web of Conferences   Vol. 41   2013

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    Publishing type:Research paper (international conference proceedings)  

    The correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified in acetylene dication by the time-resolved four-body Coulomb explosion imaging. © Owned by the authors, published by EDP Sciences, 2013.

    DOI: 10.1051/epjconf/20134102013

    Web of Science

    Scopus

  36. Ultrafast nonlinear double excitations of he in intense EUV FEL fields Reviewed

    M. Fushitani, Y. Hikosaka, A. Matsuda, C. N. Liu, T. Morishita, E. Shigemasa, A. Hishikawa

    EPJ Web of Conferences   Vol. 41   2013

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    Publishing type:Research paper (international conference proceedings)  

    Three-photon double excitation of He in intense EUV FEL fields is studied by the shot-by-shot photoelectron spectroscopy, revealing the enhancement by resonances to the doubly excited states converging to the He+ N=3 level. © Owned by the authors, published by EDP Sciences, 2013.

    DOI: 10.1051/epjconf/20134102009

    Web of Science

    Scopus

  37. Two-electron dynamics in nonlinear double excitation of helium by intense ultrashort extreme-ultraviolet pulses Reviewed

    Chien-Nan Liu, Akiyoshi Hishikawa, Toru Morishita

    PHYSICAL REVIEW A   Vol. 86 ( 5 ) page: 13   2012.11

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    We present a theoretical study for multiphoton double excitation of He atoms exposed to an intense ultrashort extreme-ultraviolet (EUV) pulse, where the photon energy coincides with the transition energy from the ground state to a Rydberg state, by solving the time-dependent Schrodinger equation in the hyperspherical coordinates. Photoelectron spectra under the conditions comparable with a recent experiment [Hishikawa et al., Phys. Rev. Lett. 107, 243003 (2011)] are calculated and analyzed. We identify the mechanism of the enhanced three-photon absorption probability which is more than one order of magnitude larger than that for the two-photon process in accordance with the experiment. The enhancement is attributed to a propensity rule for double excitation in a two-step mechanism, in which a one-photon absorption by one electron to a Rydberg state is followed by a two-photon absorption by the other electron to an excited orbital, while the first electron remains at nearly the same principle quantum number. Based on the time-dependent perturbation theory, the three-photon absorption probability exhibits peculiar cubic dependence on the pulse duration due to the propensity rule, in contrast to the linear dependence of the two-photon absorption probability. Thus a crossover between the two-and three-photon absorption probabilities takes place for sufficiently intense and long pulses. We also study the time evolution of a doubly excited two-electron wave packet created by an intense ultrashort EUV pulse efficiently using the same enhancement scheme, opening up the possibility of visualizing the correlated motion of two electrons in the time domain.

    DOI: 10.1103/PhysRevA.86.053426

    Web of Science

  38. レーザークーロン爆発イメージングによる実時間反応追跡 Invited Reviewed

    菱川明栄

    レーザー研究   Vol. 40   page: 745-751   2012.10

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    Authorship:Lead author   Language:Japanese  

  39. EUV and soft X-ray photoelectron spectroscopy of isolated atoms and molecules using single-order laser high-harmonics at 42 eV and 91 eV Reviewed

    M. Fushitani, A. Matsuda and A. Hishikawa

    J. Electron. Spectrosc. Relat. Phenom.   Vol. 184   page: 561-568   2012.2

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI: 10.1016/j.elspec.2011.10.002

  40. 極紫外自由電子レーザー場における原子のシングルショット光電子分光 Invited Reviewed

    彦坂泰正,伏谷瑞穂,菱川明栄

    しょうとつ   Vol. 9 ( 1 ) page: 5-10   2012.1

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    Authorship:Lead author   Language:Japanese  

  41. EUV and soft X-ray photoelectron spectroscopy of isolated atoms and molecules using single-order laser high-harmonics at 42 eV and 91 eV Reviewed

    Mizuho Fushitani, Akitaka Matsuda, Akiyoshi Hishikawa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 184 ( 11-12 ) page: 561 - 568   2012.1

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    Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Photoelectron spectroscopy of isolated atoms and molecules using single-order high-harmonics of Ti:Sapphire laser pulses (800 nm, 12 fs/30 fs) is demonstrated. Dielectric multilayer mirrors, SiC/Mg and Mo/Si, are used to isolate the 27th (42 eV) and 59th (91 eV) order harmonics, respectively. The obtained harmonics are characterized by valence and inner-shell photoelectron spectroscopy of Xe. The applications to two-color two-photon ionization of He and pump-probe spectroscopy of ultrafast photodissociation of Br-2, Br-2(C-1 Pi(u)) --&gt; Br(P-2(3/2))+ Br(P-2(3/2)), are presented. (C) 2011 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2011.10.002

    Web of Science

  42. Theoretical study of multi-photon double electron excitation of He by intense ultrashort EUV pulses Reviewed

    Chien-Nan Liu, Toru Morishita, Shinichi Watanabe, Akiyoshi Hishikawa

    XXVII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC 2011), PTS 1-15   Vol. 388   2012

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    Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    We use the time-dependent hypersperhical close-coupling method to study the double excitation of helium atoms by intense ultrashort XUV pulses. In addition to showing the photoelectron yield spectra, we demonstrate that free electron lasers can be used to efficiently create doubly excited electron wave packets, opening up the possibility of visualizing the correlated motion of electrons in atoms.

    DOI: 10.1088/1742-6596/388/3/032007

    Web of Science

  43. Visualizing correlated dynamics of hydrogen atoms in acetylene dication by time-resolved four-body coulomb explosion imaging Reviewed

    Akitaka Matsuda, Mizuho Fushitani, Eiji J. Takahashi, Akiyoshi Hishikawa

    Springer Proceedings in Physics   Vol. 125   page: 317 - 322   2012

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    Ultrafast hydrogenmigration in deuterated acetylene dication (C 2D2+2 ) is studied by time-resolved four-body Coulomb explosion imaging, C2D4+ 2 → D++ C ++ C ++ D +, using a pair of few-cycle intense laser pulses (9 fs, 1.3 × 1014 W/cm 2). Momentum correlation of the D+ ions produced by the full fragmentation process shows that (1) motions of the two deuterium atoms are strongly correlated during the isomerization and (2) the molecular structure deforms to nonplanar geometries. © Springer-Verlag Berlin Heidelberg 2012.

    DOI: 10.1007/978-3-642-28948-4_53

    Scopus

  44. Enhanced Nonlinear Double Excitation of He in Intense Extreme Ultraviolet Laser Fields Reviewed

    A. Hishikawa, M. Fushitani, Y. Hikosaka, A. Matsuda, C. -N. Liu, T. Morishita, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, H. Ohashi, H. Kimura, Y. Senba, M. Yabashi, T. Ishikawa

    PHYSICAL REVIEW LETTERS   Vol. 107 ( 24 ) page: 243003   2011.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    Nonlinear, three-photon double excitation of He in intense extreme ultraviolet free-electron laser fields (similar to 24.1 eV, similar to 5 TW/cm(2)) is presented. Resonances to the doubly excited states converging to the He(+) N = 3 level are revealed by the shot-by-shot photoelectron spectroscopy and identified by theoretical calculations based on the time-dependent Schrodinger equation for the two-electron atom under a laser field. It is shown that the three-photon double excitation is enhanced by intermediate Rydberg states below the first ionization threshold, giving a greater contribution to the photoionization yields than the two-photon process by more than 1 order of magnitude.

    DOI: 10.1103/PhysRevLett.107.243003

    Web of Science

  45. クーロン爆発イメージングによる超高速反応追跡 Invited

    菱川明栄

    光アライアンス   Vol. 22 ( 11 ) page: 19-22   2011.11

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    Language:Japanese  

  46. 光のゆらぎで探る:自由電子レーザー場中の原子 Invited

    伏谷瑞穂, 彦坂泰正, 菱川明栄

    光アライアンス   Vol. 22 ( 10 ) page: 25-28   2011.10

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  47. A magnetic-bottle multi-electron-ion coincidence spectrometer Reviewed

    Akitaka Matsuda, Mizuho Fushitani, Chien-Ming Tseng, Yasumasa Hikosaka, John H. D. Eland, Akiyoshi Hishikawa

    REVIEW OF SCIENTIFIC INSTRUMENTS   Vol. 82 ( 10 ) page: 103105   2011.10

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    A novel multi-electron-ion coincidence spectrometer developed on the basis of a 1.5 m-long magnetic-bottle electron spectrometer is presented. Electrons are guided by an inhomogeneous magnetic field to a detector at the end of the flight tube, while a set of optics is used to extract counterpart ions to the same detector, by a pulsed inhomogeneous electric field. This setup allows ion detection with high mass resolution, without impairing the high collection efficiency for electrons. The performance of the coincidence spectrometer was tested with double ionization of carbon disulfide, CS2 -> CS22+ + e(-) + e(-), in ultrashort intense laser fields (2.8 x 10(13) W/cm(2), 280 fs, 1030 nm) to clarify the electron correlation below the rescattering threshold. (C) 2011 American Institute of Physics. [doi:10.1063/1.3648133]

    DOI: 10.1063/1.3648133

    Web of Science

  48. Time-resolved EUV photoelectron spectroscopy of dissociating I-2 by laser harmonics at 80 nm Reviewed

    Mizuho Fushitani, Akitaka Matsuda, Akiyoshi Hishikawa

    OPTICS EXPRESS   Vol. 19 ( 10 ) page: 9600 - 9606   2011.5

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    Publishing type:Research paper (scientific journal)   Publisher:OPTICAL SOC AMER  

    Generation of single-order laser harmonics in extreme ultraviolet (EUV) and the application to the time-resolved photoelectron spectroscopy of I-2 are demonstrated. The EUV pulses at 80 nm were generated from Kr as the 5th order harmonics of intense 400 nm laser pulses and then separated from other harmonic orders by a thin indium foil. The pump-probe photoelectron spectroscopy of I-2 in the B (3)Pi(0(u)(+)) and B" (1)Pi(1(u)) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (similar to 400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states. (C) 2011 Optical Society of America

    DOI: 10.1364/OE.19.009600

    Web of Science

  49. Time-resolved EUV photoelectron spectroscopy of dissociating I(2) by laser harmonics at 80 nm Reviewed

    Fushitani, M. and Matsuda, A. and Hishikawa, A.

    Optics Express   Vol. 19 ( 10 ) page: 9600-9606   2011

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    Language:English   Publishing type:Research paper (scientific journal)  

    Generation of single-order laser harmonics in extreme ultraviolet (EUV) and the application to the time-resolved photoelectron spectroscopy of I(2) are demonstrated. The EUV pulses at 80 nm were generated from Kr as the 5th order harmonics of intense 400 nm laser pulses and then separated from other harmonic orders by a thin indium foil. The pump-probe photoelectron spectroscopy of I(2) in the B (3)Pi(0(u)(+)) and B" (1)Pi(1(u)) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (similar to 400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states. (C) 2011 Optical Society of America

  50. Visualizing hydrogen atoms migrating in acetylene dication by time-resolved three-body and four-body Coulomb explosion imaging Reviewed

    Matsuda, A. and Fushitani, M. and Takahashi, E. J. and Hishikawa, A.

    Physical Chemistry Chemical Physics   Vol. 13 ( 19 ) page: 8697-8704   2011

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    The visualization of ultrafast isomerization of deuterated acetylene dication (C(2)D(2)(2+)) is demonstrated by time-resolved Coulomb explosion imaging with sub-10 fs intense laser pulses ( 9 fs, 0.13 PW cm(-2), 800 nm). The Coulomb explosion imaging monitoring the three-body explosion process, C(2)D(2)(3+) -> D(+) + C(+) + CD(+), as a function of the delay between the pump and probe pulses revealed that the migration of a deuterium atom proceeds in a recurrent manner; One of the deuterium atoms first shifts from one carbon site to the other in a short timescale (similar to 90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation. Correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified by the time-resolved four-body Coulomb explosion imaging, C(2)D(2)(4+) - D(+) + C(+) + C(+) + D(+).

    DOI: Doi 10.1039/C0cp02333g

  51. Visualizing hydrogen atoms migrating in acetylene dication by time-resolved three-body and four-body Coulomb explosion imaging Reviewed

    Akitaka Matsuda, Mizuho Fushitani, Eiji J. Takahashi, Akiyoshi Hishikawa

    PHYSICAL CHEMISTRY CHEMICAL PHYSICS   Vol. 13 ( 19 ) page: 8697 - 8704   2011

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    Publishing type:Research paper (scientific journal)   Publisher:ROYAL SOC CHEMISTRY  

    The visualization of ultrafast isomerization of deuterated acetylene dication (C2D22+) is demonstrated by time-resolved Coulomb explosion imaging with sub-10 fs intense laser pulses ( 9 fs, 0.13 PW cm(-2), 800 nm). The Coulomb explosion imaging monitoring the three-body explosion process, C2D23+ -> D+ + C+ + CD+, as a function of the delay between the pump and probe pulses revealed that the migration of a deuterium atom proceeds in a recurrent manner; One of the deuterium atoms first shifts from one carbon site to the other in a short timescale (similar to 90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation. Correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified by the time-resolved four-body Coulomb explosion imaging, C2D24+ - D+ + C+ + C+ + D+.

    DOI: 10.1039/c0cp02333g

    Web of Science

  52. EUV SASE-FELを用いた原子の多光子多重イオン化過程の研究 Invited Reviewed

    彦坂泰正, 伏谷瑞穂, 菱川明栄

    放射光   Vol. 23 ( 5 ) page: 291-294   2010.9

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  53. Multiphoton Double Ionization of Ar in Intense Extreme Ultraviolet Laser Fields Studied by Shot-by-Shot Photoelectron Spectroscopy Reviewed

    Y. Hikosaka, M. Fushitani, A. Matsuda, C-M. Tseng, A. Hishikawa, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, H. Ohashi, H. Kimura, Y. Senba, M. Yabashi, T. Ishikawa

    PHYSICAL REVIEW LETTERS   Vol. 105 ( 13 )   2010.9

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    Photoelectron spectroscopy has been performed to study the multiphoton double ionization of Ar in an intense extreme ultraviolet laser field (h nu similar to 21 eV, similar to 5 TW/cm(2)), by using a free electron laser (FEL). Three distinct peaks identified in the observed photoelectron spectra clearly show that the double ionization proceeds sequentially via the formation of Ar(+): Ar + h nu -&gt; Ar(+) + e(-) and Ar(+) + 2h nu -&gt; Ar(2+) + e(-). Shot-by-shot recording of the photoelectron spectra allows simultaneous monitoring of FEL spectrum and the multiphoton process for each FEL pulse, revealing that the two-photon ionization from Ar(+) is significantly enhanced by intermediate resonances in Ar(+).

    DOI: 10.1103/PhysRevLett.105.133001

    Web of Science

  54. Multiphoton Double Ionization of Ar in Intense Extreme Ultraviolet Laser Fields Studied by Shot-by-Shot Photoelectron Spectroscopy Reviewed

    Hikosaka, Y. and Fushitani, M. and Matsuda, A. and Tseng, C. M. and Hishikawa, A. and Shigemasa, E. and Nagasono, M. and Tono, K. and Togashi, T. and Ohashi, H. and Kimura, H. and Senba, Y. and Yabashi, M. and Ishikawa, T.

    Physical Review Letters   Vol. 105 ( 13 ) page: 133001   2010

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    Photoelectron spectroscopy has been performed to study the multiphoton double ionization of Ar in an intense extreme ultraviolet laser field (h nu similar to 21 eV, similar to 5 TW/cm(2)), by using a free electron laser (FEL). Three distinct peaks identified in the observed photoelectron spectra clearly show that the double ionization proceeds sequentially via the formation of Ar(+): Ar + h nu -> Ar(+) + e(-) and Ar(+) + 2h nu -> Ar(2+) + e(-). Shot-by-shot recording of the photoelectron spectra allows simultaneous monitoring of FEL spectrum and the multiphoton process for each FEL pulse, revealing that the two-photon ionization from Ar(+) is significantly enhanced by intermediate resonances in Ar(+).

    DOI: Doi 10.1103/Physrevlett.105.133001

  55. Multiple Explosion Pathways of the Deuterated Benzene Trication in 9-fs Intense Laser Fields Reviewed

    Akitaka Matsuda, Mizuho Fushitani, Richard A. Thomas, Vitali Zhaunerchyk, Akiyoshi Hishikawa

    JOURNAL OF PHYSICAL CHEMISTRY A   Vol. 113 ( 11 ) page: 2254 - 2260   2009.3

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    The fragmentation of deuterated benzene (CA) in ultrashort intense laser fields (9 fs, 1 x 10(15) W/cm(2)) is studied by the ion-coincidence momentum imaging technique. Five two-body and eight three-body Coulomb explosion pathways from the trication (C6D63+), associated with the deprotonation and ring-opening reactions, are identified. It is found from the fragment momentum correlation that all the observed three-body explosion processes proceed sequentially via the two-body Coulomb explosion forming molecular dications, CmDn2+, with (m,n) = (6,5), (5,5), (5,4), (4,4), (4,3), and (3,3), which further dissociate into pairs of monocations. The branching ratio of the fragmentation pathways estimated from the number of the observed coincidence events indicates that the fragmentation is nonstatistical.

    DOI: 10.1021/jp806466x

    Web of Science

  56. Electron-ion coincidence momentum imaging of molecular dissociative ionization in intense laser fields: Application to CS2 Reviewed

    Akitaka Matsuda, Mizuho Fushitani, Akiyoshi Hishikawa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 169 ( 2-3 ) page: 97 - 101   2009.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER  

    An electron-ion coincidence momentum imaging apparatus has been developed and applied to dissociative ionization of CS2 in ultrashort intense laser fields. Photoelectron images of CS2 in 35 fs intense laser fields (2 x 10(13) W/cm(2), 800 nm, linearly polarized) recorded in coincidence with the parent ion, CS2+, show clear concentric ring patterns due to the above-threshold ionization (ATI) process. On the other hand, broad structureless distributions elongated along the direction of the laser polarization are observed in the coincidence electron images for the CS+ and S' fragment ions. The difference in the electron images indicates that the dissociative ionization does not proceed sequentially by the formation and photodissociation of CS2+ in intense laser fields. (C) 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2008.12.004

    Web of Science

  57. Electron-ion coincidence momentum imaging of molecular dissociative ionization in intense laser fields: Application to CS(2) Reviewed

    Matsuda, A. and Fushitani, M. and Hishikawa, A.

    Journal of Electron Spectroscopy and Related Phenomena   Vol. 169 ( 2-3 ) page: 97-101   2009

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    An electron-ion coincidence momentum imaging apparatus has been developed and applied to dissociative ionization of CS(2) in ultrashort intense laser fields. Photoelectron images of CS(2) in 35 fs intense laser fields (2 x 10(13) W/cm(2), 800 nm, linearly polarized) recorded in coincidence with the parent ion, CS(2)(+), show clear concentric ring patterns due to the above-threshold ionization (ATI) process. On the other hand, broad structureless distributions elongated along the direction of the laser polarization are observed in the coincidence electron images for the CS(+) and S' fragment ions. The difference in the electron images indicates that the dissociative ionization does not proceed sequentially by the formation and photodissociation of CS(2)(+) in intense laser fields. (C) 2008 Elsevier B.V. All rights reserved.

  58. Multiple Explosion Pathways of the Deuterated Benzene Trication in 9-fs Intense Laser Fields Reviewed

    Matsuda, A. and Fushitani, M. and Thomas, R. A. and Zhaunerchyk, V. and Hishikawa, A.

    Journal of Physical Chemistry A   Vol. 113 ( 11 ) page: 2254-2260   2009

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    The fragmentation of deuterated benzene (CA) in ultrashort intense laser fields (9 fs, 1 x 10(15) W/cm(2)) is studied by the ion-coincidence momentum imaging technique. Five two-body and eight three-body Coulomb explosion pathways from the trication (C(6)D(6)(3+)), associated with the deprotonation and ring-opening reactions, are identified. It is found from the fragment momentum correlation that all the observed three-body explosion processes proceed sequentially via the two-body Coulomb explosion forming molecular dications, C(m)D(n)(2+), with (m,n) = (6,5), (5,5), (5,4), (4,4), (4,3), and (3,3), which further dissociate into pairs of monocations. The branching ratio of the fragmentation pathways estimated from the number of the observed coincidence events indicates that the fragmentation is nonstatistical.

  59. Time-resolved reaction imaging by intense few-cycle laser pulses and laser high-order harmonics Reviewed

    M. Fushitani, A. Matsuda, E. J. Takahashi, A. Hishikawa

    Journal of Physics: Conference Series   Vol. 185   2009

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    We discuss two novel approaches to visualize ultrafast dynamics of polyatomic molecules using few-cycle intense laser pulses and the high-order harmonics in the soft X-ray region, respectively. First, we present the real-time Coulomb explosion imaging of ultrafast isomerization of C 2D2 2+ by using intense few-cycle laser pulses (&lt
    10 fs, ∼1 PW/cm2, ∼800 nm) to show that the hydrogen migration proceeds recurrently in competition with the molecular dissociation. Secondly, we present a new experimental setup for the real-time inner-core excitation imaging, focusing on the generation and separation of the light source using the 59th order harmonic pulses (∼91 eV) and their characteristics. © 2009 IOP Publishing Ltd.

    DOI: 10.1088/1742-6596/185/1/012009

    Scopus

  60. Acetylene-vinylidene isomerization in ultrashort intense laser fields studied by triple ion-coincidence momentum imaging Reviewed

    Akiyoshi Hishikawa, Akitaka Matsuda, Eiji J. Takahashi, Mizuho Fushitani

    JOURNAL OF CHEMICAL PHYSICS   Vol. 128 ( 8 )   2008.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER INST PHYSICS  

    The isomerization of acetylene via hydrogen migration in intense laser fields (8 X 10 14 W/cm(2)) has been investigated by coincidence momentum imaging of the three-body Coulomb explosion process, C(2)H(2)(3+)-&gt; H(+)C(+)CH(+). When ultrashort (9 fs) laser pulses are used, the angle between the momenta of C(+) and H(+) fragments exhibits a sharp distribution peaked at a small angle (similar to 20 degrees), showing that the hydrogen atom remains near the original carbon site in the acetylene configuration. On the other hand, a significantly broad distribution extending to larger momentum angles (similar to 120 degrees) is observed when the pulse duration is increased to 35 fs, indicating that the ultrafast isomerization to vinylidene is induced in the longer laser pulse, (c) 2008 American Institute of Physics.

    DOI: 10.1063/1.2828557

    Web of Science

  61. Acetylene-vinylidene isomerization in ultrashort intense laser fields studied by triple ion-coincidence momentum imaging Reviewed

    Hishikawa, A. and Matsuda, A. and Takahashi, E. J. and Fushitani, M.

    Journal of Chemical Physics   Vol. 128 ( 8 ) page: 084302   2008

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    Language:English   Publishing type:Research paper (scientific journal)  

    The isomerization of acetylene via hydrogen migration in intense laser fields (8 X 10 14 W/cm(2)) has been investigated by coincidence momentum imaging of the three-body Coulomb explosion process, C(2)H(2)(3+)-> H(+)C(+)CH(+). When ultrashort (9 fs) laser pulses are used, the angle between the momenta of C(+) and H(+) fragments exhibits a sharp distribution peaked at a small angle (similar to 20 degrees), showing that the hydrogen atom remains near the original carbon site in the acetylene configuration. On the other hand, a significantly broad distribution extending to larger momentum angles (similar to 120 degrees) is observed when the pulse duration is increased to 35 fs, indicating that the ultrafast isomerization to vinylidene is induced in the longer laser pulse, (c) 2008 American Institute of Physics.

    DOI: Doi 10.1063/1.2828557

  62. Visualizing recurrently migrating hydrogen in acetylene dication by intense ultrashort laser pulses Reviewed

    Akiyoshi Hishikawa, Akitaka Matsuda, Mizuho Fushitani, Eiji J. Takahashi

    PHYSICAL REVIEW LETTERS   Vol. 99 ( 25 )   2007.12

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    We demonstrate the visualization of ultrafast hydrogen migration in deuterated acetylene dication (C(2)D(2)(2+)) by employing the pump-probe Coulomb explosion imaging with sub-10-fs intense laser pulses (9 fs, 0.13 PW/cm(2), 800 nm). It is shown, from the temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C(2)D(2)(3+) -> D(+)+C(+)+CD(+), that the migration proceeds in a recurrent manner: The deuterium atom first shifts from one carbon site to the other in a short time scale (similar to 90 fs) and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation.

    DOI: 10.1103/PhysRevLett.99.258302

    Web of Science

  63. Dalitz plot analysis of Coulomb exploding O-3 in ultrashort intense laser fields Reviewed

    Akitaka Matsuda, Eiji J. Takahashi, Akiyoshi Hishikawa

    JOURNAL OF CHEMICAL PHYSICS   Vol. 127 ( 11 )   2007.9

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    The three-body Coulomb explosion of O-3, O-3(3+)-> O++O++O+, in ultrashort intense laser fields (2x10(15) W/cm(2)) is studied with two different pulse durations (9 and 40 fs) by the coincidence momentum imaging method. In addition to a decrease in the total kinetic energy release, a broadening in the Dalitz plot distribution [Philos. Mag. 44, 1068 (1953)] is observed when the pulse duration is increased from 9 to 40 fs. The analysis based on a simple Coulomb explosion model shows that the geometrical structure of O-3 remains almost unchanged during the interaction with the few-cycle intense laser fields, while a significant structural deformation along all the three vibrational coordinates, including the antisymmetric stretching coordinate, is identified in the 40 fs intense laser fields. The observed nuclear dynamics are discussed in terms of the population transfer to the excited states of O-3. (c) 2007 American Institute of Physics.

    DOI: 10.1063/1.2766718

    Web of Science

  64. Electronic and nuclear responses of fixed-in-space H2S to ultrashort intense laser fields (vol 97, art no 243002, 2006) Reviewed

    Akiyoshi Hishikawa, Eiji J. Takahashi, Akitaka Matsuda

    PHYSICAL REVIEW LETTERS   Vol. 98 ( 1 )   2007.1

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    DOI: 10.1103/PhysRevLett.98.019901

    Web of Science

  65. Visualizing recurrently migrating hydrogen in acetylene dication by intense ultrashort laser pulses Reviewed

    Hishikawa, A. and Matsuda, A. and Fushitani, M. and Takahashi, E. J.

    Physical Review Letters   Vol. 99 ( 25 ) page: 258302   2007

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    Language:English   Publishing type:Research paper (scientific journal)  

    We demonstrate the visualization of ultrafast hydrogen migration in deuterated acetylene dication (C(2)D(2)(2+)) by employing the pump-probe Coulomb explosion imaging with sub-10-fs intense laser pulses (9 fs, 0.13 PW/cm(2), 800 nm). It is shown, from the temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C(2)D(2)(3+) -> D(+)+C(+)+CD(+), that the migration proceeds in a recurrent manner: The deuterium atom first shifts from one carbon site to the other in a short time scale (similar to 90 fs) and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation.

    DOI: Doi 10.1103/Physrevlett.99.258302

  66. Dalitz plot analysis of Coulomb exploding O-3 in ultrashort intense laser fields Reviewed

    Matsuda, A. and Takahashi, E. J. and Hishikawa, A.

    Journal of Chemical Physics   Vol. 127 ( 11 ) page: 114318   2007

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    Language:English   Publishing type:Research paper (scientific journal)  

    The three-body Coulomb explosion of O-3, O-3(3+)-> O++O++O+, in ultrashort intense laser fields (2x10(15) W/cm(2)) is studied with two different pulse durations (9 and 40 fs) by the coincidence momentum imaging method. In addition to a decrease in the total kinetic energy release, a broadening in the Dalitz plot distribution [Philos. Mag. 44, 1068 (1953)] is observed when the pulse duration is increased from 9 to 40 fs. The analysis based on a simple Coulomb explosion model shows that the geometrical structure of O-3 remains almost unchanged during the interaction with the few-cycle intense laser fields, while a significant structural deformation along all the three vibrational coordinates, including the antisymmetric stretching coordinate, is identified in the 40 fs intense laser fields. The observed nuclear dynamics are discussed in terms of the population transfer to the excited states of O-3. (c) 2007 American Institute of Physics.

    DOI: Doi 10.1063/1.2766718

  67. Coincidence momentum imaging of two- and three-body Coulomb explosion of ethanol in intense laser fields Reviewed

    Ryuji Itakura, Takahiro Teramoto, Akiyoshi Hishikawa, Kaoru Yamanouchi

    ULTRAFAST OPTICS V   Vol. 132   page: 375 - +   2007

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    Dissociative ionization of ethanol in intense laser fields is investigated by the coincidence momentum imaging method. Two-body Coulomb explosion channels with the hydrogen migration are identified in addition to a three-body Coulomb explosion channel. On the basis of the momentum vector distributions of the fragment ions, the dissociative ionization dynamics is discussed.

    DOI: 10.1007/978-0-387-49119-6_49

    Web of Science

  68. Coulomb explosion imaging of molecular dynamics in intense laser fields Reviewed

    Akiyoshi Hishikawa, Kaoru Yamanouchi

    Springer Series in Chemical Physics   Vol. 85   page: 1 - 24   2007

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    The nuclear dynamics of polyatomic molecules in intense laser fields (∼1 PW/cm2) is studied through the momentum imaging of the fragment ions produced through Coulomb explosion. Characteristic nuclear dynamics that occur on the multidimensional potential energy surfaces in intense laser fields, such as sequential and concerted bond-breaking and hydrogen migration, are elucidated from momentum correlations among the fragment ions. © 2007 Springer-Verlag.

    DOI: 10.1007/978-3-540-38156-3-1

    Scopus

  69. Visualizing recurrently migrating hydrogen by few-cycle intense laser pulses Reviewed

    Akiyoshi Hishikawa, Akitaka Matsudal, Mizuho Fushitani, Eiji J. Takahashi

    XXV INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS   Vol. 88   page: 12056   2007

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    Ultrafast hydrogen migration in deuterated acetylene dication (C(2)D(2)(2+)) is studied by the pump-probe Coulomb explosion imaging with few-cycle intense laser pulses (9 fs, 0.13 PW/cm(2), 800 nm). The temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C(2)D(2)(3+) -&gt; D(+) + C(+) + CD(+), shows that the migration proceeds in a recurrent manner: The deuterium atom first shifts from one carbon site to the other in a short time scale (similar to 90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation.

    DOI: 10.1088/1742-6596/88/1/012056

    Web of Science

  70. Visualizing recurrently migrating hydrogen by few-cycle intense laser pulses Reviewed

    Akiyoshi Hishikawa, Akitaka Matsudal, Mizuho Fushitani, Eiji J. Takahashi

    XXV INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS   Vol. 88   2007

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    Ultrafast hydrogen migration in deuterated acetylene dication (C(2)D(2)(2+)) is studied by the pump-probe Coulomb explosion imaging with few-cycle intense laser pulses (9 fs, 0.13 PW/cm(2), 800 nm). The temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C(2)D(2)(3+) -&gt; D(+) + C(+) + CD(+), shows that the migration proceeds in a recurrent manner: The deuterium atom first shifts from one carbon site to the other in a short time scale (similar to 90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation.

    DOI: 10.1088/1742-6596/88/1/012056

    Web of Science

  71. Electronic and nuclear responses of fixed-in-space H2S to ultrashort intense laser fields Reviewed

    Akiyoshi Hishikawa, Eiji J. Takahashi, Akitaka Matsuda

    PHYSICAL REVIEW LETTERS   Vol. 97 ( 24 )   2006.12

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    The Coulomb explosion dynamics of H2S, H2S3+-> H++S++H+, in ultrashort intense laser fields (12 fs, similar to 2x10(14) W/cm(2)) is studied by the coincidence momentum imaging of the three fragment ions. Different electronic and nuclear responses are identified depending on the direction of laser polarization epsilon in the molecular frame. The dependence can be interpreted in terms of the electronic and bonding characters of charge transfer states of H2S coupled to the electronic ground state.

    DOI: 10.1103/PhysRevLett.97.243002

    Web of Science

  72. Dissociative ATI of H-2 and D-2 in intense soft x-ray laser fields Reviewed

    K Hoshina, A Hishikawa, K Kato, T Sako, K Yamanouchi, EJ Takahashi, Y Nabekawa, K Midorikawa

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 39 ( 4 ) page: 813 - 829   2006.2

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    The dissociative photoionization processes of H-2 and D-2 in an intense, short-pulsed soft x-ray field (lambda = 29.6 nm, 3 x 10(12) W CM-2, 15 fs) generated as the 27th high-order harmonic of a Ti:sapphire laser is investigated for the first time by time-of-flight mass spectrometry. The ejected H+ fragment ions from H2 are distributed in the kinetic energy range of 3-20 eV peaked at 10.0 eV, and the yield exhibits a nonlinear dependence of the order of 1.7(l) on the light field intensity of the 27th harmonic. Similarly, the D+ fragment ions from D-2 are distributed in the 3-20 eV range peaked at 10.3 eV, and the yield exhibits a nonlinear dependence of the order of 1.6 +/- 0.2. The kinetic energy distributions of H+ and D+ and the nonlinearity in their yields are interpreted well by the two coexisting ionization processes: (i) one-photon dissociative ionization and (ii) dissociative two-photon above-threshold-ionization (ATI) mainly into the repulsive 2p pi(u) state.

    DOI: 10.1088/0953-4075/39/4/007

    Web of Science

  73. Electronic and nuclear responses of fixed-in-space H2S to ultrashort intense laser fields Reviewed

    Hishikawa, A. and Takahashi, E. J. and Matsuda, A.

    Physical Review Letters   Vol. 97 ( 24 ) page: 243002   2006

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    The Coulomb explosion dynamics of H2S, H2S3+-> H++S++H+, in ultrashort intense laser fields (12 fs, similar to 2x10(14) W/cm(2)) is studied by the coincidence momentum imaging of the three fragment ions. Different electronic and nuclear responses are identified depending on the direction of laser polarization epsilon in the molecular frame. The dependence can be interpreted in terms of the electronic and bonding characters of charge transfer states of H2S coupled to the electronic ground state.

    DOI: Doi 10.1103/Physrevlett.97.243002

  74. Dissociative ATI of H-2 and D-2 in intense soft x-ray laser fields Reviewed

    Hoshina, K. and Hishikawa, A. and Kato, K. and Sako, T. and Yamanouchi, K. and Takahashi, E. J. and Nabekawa, Y. and Midorikawa, K.

    Journal of Physics B-Atomic Molecular and Optical Physics   Vol. 39 ( 4 ) page: 813-829   2006

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    Language:English   Publishing type:Research paper (scientific journal)  

    The dissociative photoionization processes of H-2 and D-2 in an intense, short-pulsed soft x-ray field (lambda = 29.6 nm, 3 x 10(12) W CM-2, 15 fs) generated as the 27th high-order harmonic of a Ti:sapphire laser is investigated for the first time by time-of-flight mass spectrometry. The ejected H+ fragment ions from H2 are distributed in the kinetic energy range of 3-20 eV peaked at 10.0 eV, and the yield exhibits a nonlinear dependence of the order of 1.7(l) on the light field intensity of the 27th harmonic. Similarly, the D+ fragment ions from D-2 are distributed in the 3-20 eV range peaked at 10.3 eV, and the yield exhibits a nonlinear dependence of the order of 1.6 +/- 0.2. The kinetic energy distributions of H+ and D+ and the nonlinearity in their yields are interpreted well by the two coexisting ionization processes: (i) one-photon dissociative ionization and (ii) dissociative two-photon above-threshold-ionization (ATI) mainly into the repulsive 2p pi(u) state.

  75. Concerted and sequential Coulomb explosion processes of N2O in intense laser fields by coincidence momentum imaging Reviewed

    M Ueyama, H Hasegawa, A Hishikawa, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 123 ( 15 )   2005.10

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    The Coulomb explosion dynamics of N2O in intense laser fields (800 nm, 60 fs, similar to 0.16 PW/cm(2)) is studied by the coincidence momentum imaging method. From the momentum correlation maps obtained for the three-body fragmentation pathway, N2O3+-&gt; N++N++O+, the ultrafast structural deformation dynamics of N2O prior to the Coulomb explosion is extracted. It is revealed that the internuclear N-N and N-O distances stretch simultaneously as the bond angle &gt; N-N-O decreases. In addition, two curved thin distributions are identified in the momentum correlation maps, and are interpreted well as those originating from the sequential dissociation pathway, N2O3+-&gt; N++NO2+-&gt; N++N++O+. (c) 2005 American Institute of Physics.

    DOI: 10.1063/1.2032988

    Web of Science

  76. Probing the ultrafast nuclear motion in CS22+ in intense laser fields Reviewed

    A Hishikawa, M Ueyama, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 122 ( 15 )   2005.4

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    The temporal evolution of the nuclear wave packet of CS(2)2+ formed in an intense laser field (60 fs, 0.13 PW/cm(2)) is traced in real time by the pump-and-probe technique combined with coincidence momentum imaging of the Coulomb explosion process, CS23+-&gt;S+ + C+ + S+. The momentum correlations among the fragment ions obtained as a function of the pump-probe time delay between 133 fs to 3 ps reveal that the nuclear wave packet in CS22+ evolves not only along the anti-symmetric stretching coordinate to yield S+ and CS+ but also along the symmetric stretching coordinate leading to the simultaneous breaking of the two C-S bonds. The contribution from two different electronic states having bent and linear-type geometrical configurations is identified in the wave packet motion along the bending coordinate of CS22+. 2005 American Institute of Physics.

    DOI: 10.1063/1.1895745

    Web of Science

  77. Probing the ultrafast nuclear motion in CS22+ in intense laser fields Reviewed

    Hishikawa, A. and Ueyama, M. and Yamanouchi, K.

    Journal of Chemical Physics   Vol. 122 ( 15 ) page: 151104   2005

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    The temporal evolution of the nuclear wave packet of CS(2)2+ formed in an intense laser field (60 fs, 0.13 PW/cm(2)) is traced in real time by the pump-and-probe technique combined with coincidence momentum imaging of the Coulomb explosion process, CS23+->S+ + C+ + S+. The momentum correlations among the fragment ions obtained as a function of the pump-probe time delay between 133 fs to 3 ps reveal that the nuclear wave packet in CS22+ evolves not only along the anti-symmetric stretching coordinate to yield S+ and CS+ but also along the symmetric stretching coordinate leading to the simultaneous breaking of the two C-S bonds. The contribution from two different electronic states having bent and linear-type geometrical configurations is identified in the wave packet motion along the bending coordinate of CS22+. 2005 American Institute of Physics.

    DOI: Doi 10.1063/1.1895745

  78. Concerted and sequential Coulomb explosion processes of N2O in intense laser fields by coincidence momentum imaging Reviewed

    Ueyama, M. and Hasegawa, H. and Hishikawa, A. and Yamanouchi, K.

    Journal of Chemical Physics   Vol. 123 ( 15 ) page: 154305   2005

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    The Coulomb explosion dynamics of N2O in intense laser fields (800 nm, 60 fs, similar to 0.16 PW/cm(2)) is studied by the coincidence momentum imaging method. From the momentum correlation maps obtained for the three-body fragmentation pathway, N2O3+-> N++N++O+, the ultrafast structural deformation dynamics of N2O prior to the Coulomb explosion is extracted. It is revealed that the internuclear N-N and N-O distances stretch simultaneously as the bond angle > N-N-O decreases. In addition, two curved thin distributions are identified in the momentum correlation maps, and are interpreted well as those originating from the sequential dissociation pathway, N2O3+-> N++NO2+-> N++N++O+. (c) 2005 American Institute of Physics.

    DOI: Doi 10.1063/1.2032988

  79. Hydrogen migration in acetonitrile in intense laser fields in competition with two-body Coulomb explosion Reviewed

    A Hishikawa, H Hasegawa, K Yamanouchi

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 141 ( 2-3 ) page: 195 - 200   2004.12

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    Two-body Coulomb explosion processes of acetonitrile (CH3CN) and deuterated acetonitrile (CD3CN), CH3CN2+ --&gt; CH3-n+ +HnCN+ and CD3CN2+ --&gt; CD3-n+ +DnCN+ (n = 0-2), in an intense laser field (0.15 pW/cm(2), 70 fs) are investigated by the coincidence momentum imaging method. The comparable yields derived for the three pathways (n = 0-2) shows that the hydrogen atom migration proceeds in competition with the Coulomb explosion. The angular distributions of the fragment ions for n = 0 exhibits a sharp peak along the laser polarization direction while the angular distribution becomes more isotropic as n increases. Based on a least-squares analysis of the fragment anisotropy, the dissociation lifetimes of the doubly charged acetonitrile were determined, from which the time scale of the hydrogen migration as well as the deformation of the C-C-N skeleton prior to the explosion were discussed. (C) 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2004.06.009

    Web of Science

  80. Nuclear dynamics on the light-dressed potential energy surface Of CS2 by coincidence momentum imaging Reviewed

    A Hishikawa, H Hasegawa, K Yamanouchi

    CHEMICAL PHYSICS LETTERS   Vol. 388 ( 1-3 ) page: 1 - 6   2004.4

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    The non-sequential three-body Coulomb explosion, CS23+ --&gt; S+ + C+ + S+, in an intense laser field (0.2 PW/cm(2), 60 fs) is studied by the coincidence momentum imaging of the fragment ions. The observed angular distribution of the momentum vectors of the two S+ ions, p(1) (S+) and p(2)(S+), exhibits a peak at an angle as small as theta(12) similar to 140degrees, showing that the nuclear motion is induced along the bending coordinate to a large extent prior to the explosion. On the other hand, the difference between their absolute values, Deltap(12) = \p(1)(S+)\ - \p(2)(S+), has a sharp distribution peaked at Deltap(12) = 0, suggesting that the symmetric stretching motion dominates over the antisymmetric stretching motion in the laser field. Based on the energy dependence of the momentum vector correlation, the characteristic nuclear dynamics of CS2 on the light-dressed potential energy surfaces in an intense laser field is discussed. (C) 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.cplett.2004.01.128

    Web of Science

  81. Hydrogen migration in acetonitrile in intense laser fields in competition with two-body Coulomb explosion Reviewed

    Hishikawa, A. and Hasegawa, H. and Yamanouchi, K.

    Journal of Electron Spectroscopy and Related Phenomena   Vol. 141 ( 2-3 ) page: 195-200   2004

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    Two-body Coulomb explosion processes of acetonitrile (CH3CN) and deuterated acetonitrile (CD3CN), CH3CN2+ --> CH3-n+ +HnCN+ and CD3CN2+ --> CD3-n+ +DnCN+ (n = 0-2), in an intense laser field (0.15 pW/cm(2), 70 fs) are investigated by the coincidence momentum imaging method. The comparable yields derived for the three pathways (n = 0-2) shows that the hydrogen atom migration proceeds in competition with the Coulomb explosion. The angular distributions of the fragment ions for n = 0 exhibits a sharp peak along the laser polarization direction while the angular distribution becomes more isotropic as n increases. Based on a least-squares analysis of the fragment anisotropy, the dissociation lifetimes of the doubly charged acetonitrile were determined, from which the time scale of the hydrogen migration as well as the deformation of the C-C-N skeleton prior to the explosion were discussed. (C) 2004 Elsevier B.V. All rights reserved.

  82. Hydrogen migration in acetonitrile in intense laser fields studied by coincidence momentum imaging Reviewed

    Hishikawa, A. and Hasegawa, H. and Yamanouchi, K.

    Physica Scripta   Vol. T110   page: 108-111   2004

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    The two-body Coulomb explosion of acetonitrile, CH3CN2+ -> CH3-n+ + HnCN+(n = 0-2), in intense laser fields (0.15 PW/cm(2), 70 fs) is studied by the coincidence momentum imaging technique. It is found that the fragment ions for n 0 are ejected mostly in the direction of the laser polarization vector with < cos(2)theta > = 0.68, where theta is the angle between the fragment recoil direction and the laser polarization vector, while the angle distribution becomes more isotropic as n increases, i.e., < cos(2)theta > = 0.49 for n = 1 and < cos(2)theta > = 0.37 for n = 2. From this characteristic correlation between the anisotropy in the fragment ejection and the hydrogen migration, the Coulomb explosion dynamics competing with the hydrogen atom transfer from the methyl group to the nitrile group is investigated.

  83. Nuclear dynamics on the light-dressed potential energy surface of CS2 by coincidence momentum imaging Reviewed

    Hishikawa, A. and Hasegawa, H. and Yamanouchi, K.

    Chemical Physics Letters   Vol. 388 ( 1-3 ) page: 1-6   2004

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    The non-sequential three-body Coulomb explosion, CS23+ --> S+ + C+ + S+, in an intense laser field (0.2 PW/cm(2), 60 fs) is studied by the coincidence momentum imaging of the fragment ions. The observed angular distribution of the momentum vectors of the two S+ ions, p(1) (S+) and p(2)(S+), exhibits a peak at an angle as small as theta(12) similar to 140degrees, showing that the nuclear motion is induced along the bending coordinate to a large extent prior to the explosion. On the other hand, the difference between their absolute values, Deltap(12) = \p(1)(S+)\ - \p(2)(S+), has a sharp distribution peaked at Deltap(12) = 0, suggesting that the symmetric stretching motion dominates over the antisymmetric stretching motion in the laser field. Based on the energy dependence of the momentum vector correlation, the characteristic nuclear dynamics of CS2 on the light-dressed potential energy surfaces in an intense laser field is discussed. (C) 2004 Elsevier B.V. All rights reserved.

  84. Hydrogen migration in acetonitrile in intense laser fields studied by coincidence momentum imaging Reviewed

    Akiyoshi Hishikawa, Hirokazu Hasegawa, Kaoru Yamanouchi

    PHYSICA SCRIPTA   Vol. T110   page: 108 - 111   2004

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    The two-body Coulomb explosion of acetonitrile, CH3CN2+ -> CH3-n+ + HnCN+(n = 0-2), in intense laser fields (0.15 PW/cm(2), 70 fs) is studied by the coincidence momentum imaging technique. It is found that the fragment ions for n 0 are ejected mostly in the direction of the laser polarization vector with < cos(2)theta > = 0.68, where theta is the angle between the fragment recoil direction and the laser polarization vector, while the angle distribution becomes more isotropic as n increases, i.e., < cos(2)theta > = 0.49 for n = 1 and < cos(2)theta > = 0.37 for n = 2. From this characteristic correlation between the anisotropy in the fragment ejection and the hydrogen migration, the Coulomb explosion dynamics competing with the hydrogen atom transfer from the methyl group to the nitrile group is investigated.

    DOI: 10.1238/Physica.Topical.110a00108

    Web of Science

  85. Hydrogen migration in acetonitrile in intense laser fields studied by coincidence momentum imaging Reviewed

    Akiyoshi Hishikawa, Hirokazu Hasegawa, Kaoru Yamanouchi

    Physica Scripta T   Vol. T110   page: 108 - 111   2004

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    The two-body Coulomb explosion of acetonitrile, CH3CN 2+ → CH3-n+ + HnCN+ (n = 0-2), in intense laser fields (0.15 PW/cm2, 70 fs) is studied by the coincidence momentum imaging technique. It is found that the fragment ions for n = 0 are ejected mostly in the direction of the laser polarization vector with 〈 cos2 θ 〉 = 0.68, where θ is the angle between the fragment recoil direction and the laser polarization vector, while the angle distribution becomes more isotropic as n increases, i.e., 〈 cos2 θ 〉 = 0.49 for n = 1 and 〈 cos2 θ 〉 = 0.37 for n = 2. From this characteristic correlation between the anisotropy in the fragment ejection and the hydrogen migration, the Coulomb explosion dynamics competing with the hydrogen atom transfer from the methyl group to the nitrile group is investigated. © Physica Scripta 2004.

    DOI: 10.1238/Physica.Topical.110a00108

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  86. Sequential three-body Coulomb explosion of CS2 in intense laser fields appearing in momentum correlation map Reviewed

    A Hishikawa, H Hasegawa, K Yamanouchi

    CHEMICAL PHYSICS LETTERS   Vol. 361 ( 3-4 ) page: 245 - 250   2002.7

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    The three-body Coulomb explosion process of CS2 in intense laser fields (60 fs, 0.36 x 10(15) W/cm(2)), CS23+ --&gt; S+ + C+ + S+, is studied by the triple coincidence momentum imaging of the atomic fragment ions. The set of the observed momentum vectors of the fragment ions determined for respective explosion events exhibits a clear trajectory originating from the rotational motion of an intermediate CS2+ ion, formed in a sequential explosion process of CS23+ prior to the complete three-body fragmentation. The contribution of the sequential pathway to the overall three-body explosion process is estimated to be 17(1)%. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0009-2614(02)00880-1

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  87. Suppression of decomposition of aniline cation in intense laser fields by cluster formation with ammonia molecules Reviewed

    J Watanabe, R Itakura, A Hishikawa, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 116 ( 22 ) page: 9697 - 9702   2002.6

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    Mass-selected aniline cations and [aniline-(NH3)(n)](+) (n=1 and 2) cluster ions are exposed to the femtosecond laser fields (lambdasimilar to395 nm,Isimilar to4x10(15) W/cm(2)) and the nanosecond laser fields (lambda=532 nm,Isimilar to2.7x10(10) W/cm(2)) by using a tandem type time-of-flight mass spectrometer. In the case of the bare aniline cation, the decomposition forming the five-membered ring compound, cyclopentadienyl cation (C5H6+), dominantly proceeds in both the femtosecond and nanosecond laser fields. When one or two ammonia molecules are attached to the aniline cation, the decomposition is significantly suppressed. This suppression was interpreted in terms of an intermolecular energy flow through the hydrogen bonding. (C) 2002 American Institute of Physics.

    DOI: 10.1063/1.1475753

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  88. Coincidence Imaging of coulomb explosion of CS2 in intense laser fields Reviewed

    H Hasegawa, K Doi, A Hishikawa, K Yamanouchi

    SCIENCE OF SUPERSTRONG FIELD INTERACTIONS   Vol. 634   page: 197 - 198   2002

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    The coincidence imaging technique is applied to direct determination of the momentum vectors of all the fragment ions produced through every event of the Coulomb explosion of a single molecular ion, CS2+ (z = 2 - 4) formed in intense laser fields (0.36 PW/cm(2)). The molecular structure Of CS23+ just before the three-body Coulomb explosion is reconstructed from the measured momentum vectors of the atomic fragment ions. It was confirmed that the skeletal deformation of CS2 is induced to a large extent in intense laser fields.

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  89. Coincidence imaging of Coulomb explosion of CS2 in intense laser fields Reviewed

    H Hasegawa, A Hishikawa, K Yamanouchi

    CHEMICAL PHYSICS LETTERS   Vol. 349 ( 1-2 ) page: 57 - 63   2001.11

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    The coincidence imaging technique is applied to direct determination of the momentum vectors of all the fragment ions produced through every event of the Coulomb explosion of a single molecular ion, CS22+ (z = 2-4) formed in intense laser of CS23+ just fields (similar to 60 fs, 0.36 x 10(15) W/cm(2)). The molecular structure I before the Coulomb explosion, CS23+ --&gt; S+ + C+ + S+, is reconstructed from the measured momentum vectors of the fragment ions. The mean C-S bond length of &lt;r &gt; = 2.5 Angstrom and the azimuthally averaged S-C-S bond angle, &lt; gamma &gt; = 145 degrees, thus determined indicate that structural deformation occurs to a large extent in the intense laser fields. (C) 2001 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0009-2614(01)01087-9

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  90. Real-time probing of alignment and structural deformation of CS2 in intense nanosecond laser fields Reviewed

    A Iwasaki, A Hishikawa, K Yamanouchi

    CHEMICAL PHYSICS LETTERS   Vol. 346 ( 5-6 ) page: 379 - 386   2001.10

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    A time evolution of the alignment and structural deformation processes of neutral CS2 in intense non-resonant nanosecond laser fields (1.9 X 10(12) W/cm(2)) is derived by ionizing CS2 using intense circularly polarized feintosecond laser fields (5.5 x 10(14) W/cm(2)). From the real-time probing of the momentum distribution of the resultant S3+ and C2+ fragment ions produced through the Coulomb explosion induced by the intense fenitosecond laser fields, it is identified that the alignment and the structural deformation proceed simultaneously in the nanosecond laser fields. (C) 2001 Elsevier Science BN. All rights reserved.

    DOI: 10.1016/S0009-2614(01)00963-0

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  91. Light-induced multiple electronic-state coupling of O-2(+) in intense laser fields Reviewed

    A Hishikawa, SL Liu, A Iwasaki, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 114 ( 22 ) page: 9856 - 9862   2001.6

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    The dissociation processes, O-2(+)--&gt;O++O, in intense laser fields (100 fs, similar to 3x10(14) W/cm(2)) are studied at the laser wavelength of 795 and 398 nm on the basis of the momentum imaging maps of the O+ fragment ions. The covariance map measurements are performed with high momentum resolution to assign securely the dissociation pathways. From the anisotropic momentum distribution of O+ with respect to the laser polarization direction, the electronic states of O-2(+) are found to be coupled exclusively through parallel transitions in the course of the dissociation process. The released kinetic energy of O+ for both 795 and 398 nm are interpreted consistently by a sequential coupling model of light-dressed potential curves of O-2(+) in the quartet Pi state manifold. (C) 2001 American Institute of Physics.

    DOI: 10.1063/1.1368383

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  92. Ionization and fragmentation dynamics of benzene in intense laser fields by tandem mass spectroscopy Reviewed

    R Itakura, J Watanabe, A Hishikawa, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 114 ( 13 ) page: 5598 - 5606   2001.4

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    Using a tandem time-of-flight mass spectrometer, benzene cations produced by the resonantly enhanced multiphoton ionization are mass separated and are exposed to intense laser fields (similar to 2x10(16) W/cm(2)) at lambda similar to 790 and 395 nm with the pulse duration of similar to 50 fs. Comparing the yields of the product ions with those obtained from neutral benzene molecules, the ionization and dissociation dynamics of benzene in intense laser fields is investigated. At lambda similar to 790 nm, the formation of parent benzene ions is a dominant process irrespective of the initial charge states, i.e., major products obtained when starting from neutral benzene are benzene cations and dications and those obtained when starting from benzene cation are benzene dications. On the other hand, at lambda similar to 395 nm, the fragmentation processes to produce C4Hi+(i=2-4) and C3Hj+(j=1-3) dominate over further ionization to the benzene dication for both cases starting from neutral benzene and benzene cation, indicating the population trapping occurs by the efficient confinement in the light-dressed mixture of the C and X states of benzene cations assisted by the ultrafast intramolecular decay process. (C) 2001 American Institute of Physics.

    DOI: 10.1063/1.1352619

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  93. Resonance-state selective photodissociation of OCS (2(1)Sigma(+)): Rotational and vibrational distributions of CO fragments Reviewed

    R Itakura, A Hishikawa, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 113 ( 16 ) page: 6598 - 6607   2000.10

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    The rotational and vibrational state distributions of the CO fragments produced through the photodissociation of OCS in the vacuum ultraviolet (VUV) region (150-155 nm), OCS (2 (1)Sigma (+))--&gt; CO (X (1)Sigma (+))+S(S-1), are derived for the three lowest quasi-bound vibrational resonances (upsilon*=0-2) in the 2 (1)Sigma (+) state. The rotational state distributions of the CO fragments in the upsilon (CO)=0 and 1 vibrational states are determined, respectively, by the analysis of the rotational structures in the laser-induced fluorescence (LIF) spectra of the A(1)Pi -X (1)Sigma (+)(0,0) and (1,1) transitions of CO. The rotational temperatures of CO in the upsilon (CO)=0 state are low (similar to 100 K) for all the three resonances, while those in the upsilon (CO)=1 state are substantially higher, i.e., 2210, 940, and 810 K for upsilon*=0, 1, and 2, respectively. The vibrational state distributions of CO are derived from the Doppler spectroscopy of the counterpart S(S-1) fragments. From the analysis of the observed Doppler profiles, it is found for all the three lowest vibrational resonances of OCS that the vibrational distributions are represented well by the Boltzmann-type distribution with a vibrational temperature of around 7000 K. On the basis of these new findings, the energy partitioning in the photodissociation process through these three vibrational resonances in the 2 (1)Sigma (+) state is discussed. (C) 2000 American Institute of Physics. [S0021-9606(00)01740-2].

    DOI: 10.1063/1.1310606

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  94. Extraction of molecular dynamics in intense laser fields from mass-resolved momentum imaging maps: application to Coulomb explosion of NO Reviewed

    A Iwamae, A Hishikawa, K Yamanouchi

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 33 ( 2 ) page: 223 - 240   2000.1

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    The nuclear dynamics of NO in intense laser fields (similar to 1.4 PW cm(-2)) is studied on the basis of the momentum-scaled time-of-flight spectra and mass-resolved momentum imaging maps of the atomic fragment ions, NP+ and Oq+ (p, q = 1-3), produced from the (p, q) Coulomb explosion pathways of NO, i.e. NO(p+q)+ --&gt; Np+ + Oq+. A procedure to extract nuclear dynamics from the momentum maps is proposed by taking account of the effect of the finite detector size. The resultant nine (p, q) single-pathway components show that (a) the distributions of the N-O internuclear distance of NOz+ just before the Coulomb explosion exhibit significant broadening (similar to 1 Angstrom); (b) the distance at which the corresponding distribution takes a maximum increases from 1.68 to 2.34 Angstrom as z from 2 to 6 with a small amount of suppression at odd z (z = 3, 5); and (c) the atomic fragment ions exhibit narrower angular distributions for a larger total charge z (= p + q) of NOz+.

    DOI: 10.1088/0953-4075/33/2/308

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  95. Ultrafast structural deformation of polyatomic molecules in intense laser fields Reviewed

    K Yamanouchi, A Hishikawa, A Iwamae, SL Liu

    PHYSICS OF ELECTRONIC AND ATOMIC COLLISIONS   Vol. 500   page: 182 - 191   2000

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    The momentum vector distributions of fragment ions produced through the Coulomb explosion of small molecules such as NO, CO2, NO2, and H2O in intense laser fields (similar to 1 PW/cm(2)) are measured by the mass-resolved momentum imaging (MRMI) technique. For NO, the MRMI maps for a single (p,q) pathway, NO(p+q)+ --&gt; NP+ + Oq+ (p, q = 1 similar to 3), are extracted from the observed MRMI maps on the basis of the momentum matching of the NP+ and Oq+. ion pair. In the MRMI maps for the fragment ions produced from CO2, NO2, and H2O, their ultrafast structural deformation both along the stretching coordinate and along the bending coordinate is identified. The &lt;O-C-O angle distribution of CO2 Spreads significantly (FWHM similar to 40 degrees), and the &lt;O-N-O bond angle of NO2 increases toward a linear configuration within the ultrashort duration of the laser pulse. This type of deformation is also identified for H2O. These structural deformations are most reasonably interpreted as a consequence of the formation of light-dressed potential energy surfaces.

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  96. Ultrafast structural deformation of NO2 in intense laser fields studied by mass-resolved momentum imaging Reviewed

    A Hishikawa, A Iwamae, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 111 ( 19 ) page: 8871 - 8878   1999.11

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    The ultrafast structural deformation of NO2 in an intense laser field (1.0 PW/cm(2)) is studied by mass-resolved momentum imaging (MRMI) of the Op+ and Nq+ (p,q=1-3) fragment ions produced from NO2z+ through the Coulomb explosion processes, NO2z+--&gt; Op++Nq++Or+ (z=p+q+r). The N-O distance just before the Coulomb explosion is elongated significantly from that in the electronic ground state, and it monotonically increases from 1.7 to 2.1 Angstrom as z increases from 4 to 9. The angle O-N-O bond angle increases toward a linear configuration as a function of z, which is interpreted in terms of the formation of the light-dressed potential energy surfaces. The two-body fragmentation pathways to produce NO+ and NO2+ are also investigated by the MRMI measurements to derive the extent of the asymmetrical bond elongation of one of the two N-O bonds. (C) 1999 American Institute of Physics. [S0021-9606(99)00443-2].

    DOI: 10.1063/1.480233

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  97. Ultrafast deformation of the geometrical structure of CO2 induced in intense laser fields Reviewed

    A Hishikawa, A Iwamae, K Yamanouchi

    PHYSICAL REVIEW LETTERS   Vol. 83 ( 6 ) page: 1127 - 1130   1999.8

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    Ultrafast deformation of geometrical structure of CO2 in an intense laser field (1.1 PW/cm(2) = 1.1 X 10(15) W/cm(2)) was investigated by momentum imaging of the fragment Op+ and Cq+ (p, q = 1-3) ions produced from CO2z+ through the Coulonnb explosion processes, CO2z+ --&gt; Op+ + Cq+ + Or+ (z = p + q + r). The observed large mean amplitude along the angle O-C-O bond angle (similar to 40 degrees) was attributed to the ultrafast bending motion induced on the light-dressed potential energy surfaces.

    DOI: 10.1103/PhysRevLett.83.1127

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  98. Vibrational propensity in the predissociation rate of SO2((C)over-tilde(1)B(2)) by two types of nodal patterns in vibrational wavefunctions Reviewed

    T Sako, A Hishikawa, K Yamanouchi

    CHEMICAL PHYSICS LETTERS   Vol. 294 ( 6 ) page: 571 - 578   1998.9

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    The absorption and laser-induced fluorescence spectra of the (C)over-tilde(1)B(2)-(X)over-tilde(1)A(1), band of SO2 were simultaneously measured between 221.5 and 208 nm under jet-cooled conditions. The fluorescence quantum yields above the dissociation threshold showed irregularity, reflecting a level specificity in the predissociation rate. The vibronic-level dependence in the predissociation rate was interpreted in terms of the nodal structure of the vibrational wavefunctions, constructed from a least-squares analysis of the observed vibrational energies in the C state. The vibrational wavefunctions can be categorized into two types of localized wavefunctions: one stretching along the dissociation coordinate which tends to afford a much faster dissociation rate than the other which folds perpendicularly to the dissociation coordinate. (C) 1998 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/s0009-2614(98)00922-1

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  99. Coulomb explosion dynamics of N-2 in intense laser field by mass-resolved momentum imaging Reviewed

    A Hishikawa, A Iwamae, K Hoshina, M Kono, K Yamanouchi

    CHEMICAL PHYSICS   Vol. 231 ( 2-3 ) page: 315 - 329   1998.6

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    The Coulomb explosion reactions of N-2, N-2((p+q)+) --&gt; Np+ + Nq+ caused by the irradiation of intense laser light (0.73-6.9 PW/cm(2)) were investigated by high-resolution time-of-flight (TOF) mass spectroscopy and by the mass-resolved two-dimensional momentum imaging (MRMI) method. Six explosion pathways(p, q) = (1, 1), (1,2), (1,3), (2, 2), (2, 3) and (3, 3) in addition to (0, 1), (0,2) dissociation pathways were identified, whose assignments were securely performed both from the momentum matching between the fragment pair and their correlation with the laser-field intensity dependence. The MRMI method, which visualizes the radial and angular momentum distributions of mass-selected fragment ions on a two-dimensional momentum plane, was used to correlate ion fragments produced after the Coulomb explosion. By examining theoretically synthesized MRMI maps, it was found that the momentum distributions of the fragment ions in a wide momentum range can be extracted by the MRMI technique. The relative yields of the explosion pathways at six different laser-field intensities were evaluated from the three-dimensional integration of the MRMI maps, and the intensity dependence of the formation of singly and multiply charged parent N-2((p+q) +) ions prior to the fragmentation was derived. (C) 1998 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0301-0104(98)00025-1

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  100. Omega-type doubling reversal in the B-3 Pi(1) state of (HgAr)-Hg-200 as a probe of the long-range potential of the A(3)Pi(0)+ state Reviewed

    A Hishikawa, H Sato, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 108 ( 22 ) page: 9202 - 9205   1998.6

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    The mass-resolved excitation spectrum of the B (II1)-I-3-X(1)Sigma(+) transition of HgAr was measured by the two-color resonantly enhanced two-photon ionization method using a high-resolution reflectron time-of-flight mass spectrometer. The rotational structures were recorded with high spectral resolution (similar to 0.05 cm(-1))for the (upsilon(B),0) bands (upsilon(B) = 0 - 9) of a single isotopomer (HgAr)-Hg-200. From the rotational analysis, the presence of an Omega-type doubling was identified for the first time, which is caused by the rotational perturbation from the nearby highly excited vibrational levels of the A (II0+)-I-3 state. The spacing between the Omega-type doublers was found to exhibit a characteristic reversal as a function of upsilon(B). From the deperturbation of the Omega-type doubling, the vibrational level energies of the A state in the vibrationally highly excited region were derived, from which its long-range interaction potential was determined. (C) 1998 American Institute of Physics. [S0021-9606(98)02822-0].

    DOI: 10.1063/1.476415

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  101. Mass-resolved VUV laser spectroscopy of XeAr: Two competing predissociation pathways in the C1 state Reviewed

    SL Liu, A Hishikawa, K Yamanouchi

    JOURNAL OF CHEMICAL PHYSICS   Vol. 108 ( 13 ) page: 5330 - 5337   1998.4

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    Mass-resolved excitation spectra of the C1-X0(+) band of XeAr were measured under jet-cooled conditions using a tunable coherent vacuum ultraviolet (VUV) light (lambda similar to 130 nm) as an excitation light source and a high-resolution (m/Delta m similar to 1100) reflectron time-of-flight mass spectrometer. The rotational structure of the C1-X0(+) (upsilon',0) (upsilon'=2-6) vibronic bands were recorded by monitoring the parent (XeAr+)-Xe-132-Ar-40 ions and the fragment Xe-132(+) ions. From the analysis of the rotational structures, the existence of the two dissociation pathways from the C1 state was identified for the first time; i.e., (i) the rotationally dependent predissociation caused by an electron-rotation interaction (L- and/or S-uncoupling) with the dissociative state with 0(-) symmetry correlating with the Xe 6s'(1/2)(0) level, and (ii) the rotationally independent predissociation caused by the electrostatic interaction with a repulsive state with Omega = 1 symmetry correlated either with the Xe 6s(3/2)(1) level or the Xe 6s(3/2)(2) level. From the least-squares fit to the partially resolved rotational structures, the dissociation rates for these two pathways as well as the band origins and the rotational constants, were derived for the upsilon'=2-6 levels in the C1 state. (C) 1998 American Institute of Physics. [S0021-9606(98)01513-X].

    DOI: 10.1063/1.475968

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  102. Rotational predissociation dynamics of H2O ((C)over-tilde(1)B(1)) by VUV laser-induced photofragment fluorescence spectroscopy Reviewed

    SL Liu, A Hishikawa, K Yamanouchi

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   Vol. 71 ( 2 ) page: 355 - 362   1998.2

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    The rotational predissociation of water molecules in the vibrationless level of the (C) over tilde B-1(1) state was investigated under jet-cooled conditions (27-154 K) by exciting them with a tunable VUV laser in the wavelength range of 124.3-123.7 nm and by detecting the total fluorescence from electronically excited photofragments OH(A(2)Sigma (+)). Due to the simple one-photon selection rule and the efficient rotational cooling, individual low-J rotational transitions of the (C) over tilde B-1(1)-(X) over tilde (1)A(1) origin band were observed with almost no overlap in the laser-induced photofragment fluorescence (LIPF) spectrum. The widths and intensities of these rotational transitions exhibited pronounced dependence on the parent rotational levels in the (C) over tilde B-1(1) state. The least-squares analysis of the observed line-widths (FWHM) of the resolved rotational transitions, Gamma 's, showed that they are well described by the formula, Gamma = Gamma (0) + a(a)[J(a)'(2)], with optimized parameters Gamma (0) = 2.5(1) cm(-1) and a(a) = 0.63(1) cm(-1), indicating that (i) the homogeneous interaction couples the (C) over tilde B-1(1) state with the (A) over tilde B-1(1) state to form OH fragments in the electronically ground (2)Pi (i) state and (ii) the heterogeneous (a-axis orbital-rotation) interaction couples the (C) over tilde B-1(1) state with the (B) over tilde (1)A(1) state to form OH fragments in the electronically excited A(2)Sigma (+) state. By taking account of the rotational line-broadening effect, the least-squares analysis was also performed to fit the observed spectral intensities to derive the branching ratio of the OH(A(2)Sigma (+)) formation via the (B) over tilde (1)A(1) state of H2O. It was found that the OH(A(2)Sigma (+)) formation branching ratio can be expressed by an exponential form, exp(-gamma [J(a)'(2)]), which was proposed first by Hodgson et al. [Mol. Phys., 54, 351 (1985)], and reproduces well the observed rotational intensity pattern when gamma = 0.097(7). By using this branching ratio and the previous data for the absorption oscillator strength, the absolute cross section to yield OH(A(2)Sigma (+)) photofragments was obtained as a function of the excitation energy.

    DOI: 10.1246/bcsj.71.355

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  103. Cross section for disalignment of excited neon atoms due to neon or helium atom collisions Reviewed

    T Wakabayashi, A Yamamoto, T Yaneda, T Furutani, A Hishikawa, T Fujimoto

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 31 ( 2 ) page: 341 - 359   1998.1

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    In a positive column plasma of glow discharge in neon the population of metastable atoms (2p(5)3s configuration) is substantial. Linearly polarized pulsed laser light excited these atoms to one of the 2p(5)3p configuration levels, and the direct fluorescence was observed with its polarized components resolved. From the temporal development of the intensities of these components, the disalignment (depolarization) rate due to atom (neon or helium) collisions was determined. From its atom-density (&lt;3 x 10(23) m(-3)) dependence the rate coefficient was determined, and from the temperature (42-650 K) dependence of the rate coefficient, the disalignment collision cross section was estimated as a function of energy in the energy range of the order of 10 meV. The cross section of the 2p(2) (Paschen notation) atoms has positive dependence on energy, while that of the 2p(7) atoms has a negative dependence. The cross sections thus determined serve asa quantitative test of the molecular potentials to the order of 1 cm(-1).
    In order to confirm that the temperature of the metastable atoms in the plasma is equal to the temperature of the surrounding wall, an additional experiment was performed; the line profile of the CW laser-induced fluorescence was observed for a plasma at liquid nitrogen temperature, and the metastable atom temperature was found to be 78 K.

    DOI: 10.1088/0953-4075/31/2/015

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  104. Mass-resolved two-dimensional momentum imaging of the Coulomb explosion of N-2 and SO2 in an intense laser field Reviewed

    A Hishikawa, A Iwamae, K Hoshina, M Kono, K Yamanouchi

    CHEMICAL PHYSICS LETTERS   Vol. 282 ( 3-4 ) page: 283 - 291   1998.1

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    The Coulomb explosion reactions of N-2 and SO2 caused by the irradiation of intense laser light were investigated by high-resolution mass spectroscopy. For N-2, from the least-squares fit to the split mass patterns for the N+, N2+ and N3+ channels, kinetic energy releases of six explosion pathways were determined. By rotating the laser polarization direction with respect to the detection axis, angular distributions for the singly and multiply charged atomic ion fragments were obtained and were converted to mass-resolved two-dimensional momentum imaging (MRMI) maps. This MRMI method was found to be useful to correlate ion fragments produced after the Coulomb explosion. MRMI was also applied to the Coulomb explosion of SO2. (C) 1998 Elsevier Science B.V.

    DOI: 10.1016/S0009-2614(97)01325-0

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  105. Coulomb explosion dynamics of N2O in intense laser-field: Identification of new two-body and three-body fragmentation pathways Reviewed

    A Hishikawa, A Iwamae, K Hoshina, M Kono, K Yamanouchi

    RESEARCH ON CHEMICAL INTERMEDIATES   Vol. 24 ( 7 ) page: 765 - 784   1998

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    The Coulomb explosion process of N2O in an intense laser-field (similar to 5 PW/cm(2)) has been investigated by the high-resolution time-of-flight (TOF) spectroscopy. Six two-body explosion pathways involving the NO+, NO2+, N-2(+) molecular ions have been securely identified from the momentum-scaled TOF spectra of the fragment ions. Assuming a linear geometry, three-body explosion pathways were investigated by sequential and concerted explosion models, When the concerted model is adopted, the observed momentum distributions of six atomic ion channels; N+, N2+, N3+, O+, O2+ and O3+, were well fitted using the Gaussian momentum distribution with the optimized bond elongation factor of 2.2(3). From the yields of individual Coulomb explosion pathways determined by the fit, the abundance of the parent ions, N2Oz+ (z = 2-8), prior to the two- body and three-body explosion processes was found to have a smooth distribution with a maximum at z similar to 3.

    DOI: 10.1163/156856798x00401

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  106. Experimental and theoretical exploration of photodissociation of SO2 via the (C)over-tilde(1)B(2) state: identification of the dissociation pathway Reviewed

    H Katagiri, T Sako, A Hishikawa, T Yazaki, K Onda, K Yamanouchi, K Yoshino

    JOURNAL OF MOLECULAR STRUCTURE   Vol. 413   page: 589 - 614   1997.9

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    The photodissociation reaction of SO2 via the (C) over tilde(1)B(2) state, SO2 ((C) over tilde(1)B(2)) --&gt; SO((3) Sigma(-)) + O(P-3) was investigated by experimental and theoretical approaches cooperatively to clarify its dissociation mechanism. We measured the laser induced fluorescence (LIF) spectrum of the (C) over tilde-(X) over tilde band in the short UV wavelength region (210-200 nm) under jet-cooled conditions. The fluorescence quantum yields and the dissociation rates of individual vibronic levels were determined in the 220-200-nm region using (i) the LIF spectrum measured in the present study, (ii) that measured previously by Yamanouchi et al. (J. Mol. Struct, 352/353 (1995) 541) in the longer wavelength region above 210 nm, and (iii) the high-resolution absorption spectrum measured by Freeman et al. (Planet. Space. Sci. 32 (1984) 1125). The dissociation rates were also derived in the 210-200-nm region from the broadening of the rotational lines of the (C) over tilde-(X) over tilde vibronic transitions. It was found that the dissociation rates determined through two different procedures were consistent with each other, and that the rate increases almost exponentially as an excess energy above the dissociation threshold increases though there is a certain fluctuation of the dissociation rates reflecting a mode specificity. We also performed theoretical ab initio calculations to derive potential energy surfaces (PESs) of the electronic ground states and low-lying electronically excited states of SO2 within the MCSCF and MRCI levels. The theoretical calculations showed that (i) the PES of the 2(1)A' state (the (C) over tilde(1)B(2) state in C-2r symmetry), correlating with the SO((1) Delta) + O(D-1) asymptote, crosses with the repulsive singlet (3(1)A') state, correlating with the SO((3) Sigma(-)) + O(P-3) asymptote, to form a pseudo-seam, (ii) the crossing pseudo-seam of these two PESs is located near the equilibrium bent angles for the X and C states along the energy contour of similar to 9700 cm(-1) measured from the SO((3) Sigma(-)) + O(P-3) dissociation limit, and (iii) the crossing seam between the 2(1)A' ((C) over tilde(1)B(2)) and repulsive 2(3)A' states is located in a lower energy region than the singlet seam; at similar to 6700 cm(-1) measured from the SO((3) Sigma(-)) + O(P-3) dissociation limit. On the basis of the above experimental and theoretical results together with the previous experimental evidence, we propose that (i) the photodissociation reaction via the (C) over tilde state proceeds mainly through the vibronic mixing between the (C) over tilde state vibronic levels with the quasi-bound dissociation continuum of the electronic ground X(1)A(1) state, and (ii) the additional dissociation channels may be open through the crossing seam with the repulsive singlet (3(1)A') state and that with the repulsive tiplet (2(3)A') slate in their narrow crossing energy regions. (C) 1997 Elsevier Science B.V.

    DOI: 10.1016/S0022-2860(97)00199-3

    Web of Science

  107. PHOFEX spectroscopy of HgNe and HgAr: Determination of the dissociation energies of the X-1 Sigma(+), A(3)II(0)+, and (BII1)-I-3 states Reviewed

    T Tasaka, K Onda, A Hishikawa, K Yamanouchi

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   Vol. 70 ( 5 ) page: 1039 - 1045   1997.5

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    Photofragment excitation (PHOFEX) spectroscopy was applied to determine the dissociation energies of the B-3 Pi(1) states of HgAr and HgNe. The PHOFEX spectra were measured in the wavelength region where the laser-induced fluorescence spectrum of the B-3 Pi(1)-X-1 Sigma(+) transition exhibits a continuum structure by probing the photolysis product of Hg(6(3)P(1)) through the Hg(8(3)S(1)-6(3)P(1)) transition. By the spectral simulation of the threshold behavior of the high-resolution (Delta v approximate to 0.08 cm(-1)) PHOFEX spectrum, the thresholds for the photodissociation reaction, HgRg --&gt; Hg(6(3)P(1)) + Rg, were determined to be 39447.9(3) and 39536.0(5) cm(-1) for Rg = Ne and Ar, respectively. From these thresholds, the dissociation energies, D-0's, of the B-3 Pi(1) states of HgNe and HgAr were determined to be D-0(B-3 Pi(1); HgNe)= 9.8(3) and Do(B-3 pi(1); HgAr)= 61.8(5) cm(-1), respectively. This direct determination of the dissociation energies of the B-3 Pi(1) states led to a determination of the D-0's for the X-1 Sigma(+) and A(3) Pi(0+) states; D-0(X-1 Sigma(+); HgNe)= 35.6(3), D-0(X-1 Sigma(+); HgAr)= 123.7(5), D-0(A(3) Pi(0+); HgNe)= 68.7(3), and D-0(A(3) Pi(0+); HgAr)= 348.8(6) cm(-1) In addition, the (v',0) vibronic bands of the B-3 Pi(1)-X-1 Sigma(+) transition of HgAr were re-measured with high resolution for v' = 0-8. From the transition wavenumbers of these vibronic bands, the Morse potential parameters were determined with high precision as omega(e) = 11.94(3) cm(-1) and omega(e)x(e) = 0.594(3) cm(-1).

    DOI: 10.1246/bcsj.70.1039

    Web of Science

  108. Radiative lifetime measurements of the B (2)Sigma(+) state of BaH by laser spectroscopy Reviewed

    LE Berg, K Ekvall, A Hishikawa, S Kelly

    PHYSICA SCRIPTA   Vol. 55 ( 3 ) page: 269 - 272   1997.3

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    By applying laser resonance methods in the near infrared wavelength region around 900 nm, a time-resolved experiment has been performed on the low lying B (2) Sigma(+) state of barium hydride. The radiative lifetime is shown to vary with the rotational quantum number due to perturbations between the low lying A' 2 Delta, A (2) Pi and B (2) Sigma(+) states. The following lifetime was obtained for the BaH molecule, where local perturbations are assumed to be negligible:
    tau(B (2) Sigma(+)(upsilon' = 0, J = 5.5))= 125 +/- 2ns.

    DOI: 10.1088/0031-8949/55/3/003

    Web of Science

  109. Femtosecond transition-state dynamics of dissociating OCS on the excited (1)Sigma(+) potential energy surface Reviewed

    A Hishikawa, K Ohde, R Itakura, SL Liu, K Yamanouchi, K Yamashita

    JOURNAL OF PHYSICAL CHEMISTRY A   Vol. 101 ( 4 ) page: 694 - 704   1997.1

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    Ultrafast photodissociation dynamics of OCS on the dissociative potential energy surface (PES) of the electronically excited (1) Sigma(+) state was investigated by photofragment excitation (PHOFEX) spectroscopy and time-dependent wavepacket calculations. The high-resolution PHOFEX spectrum of the entire (1) Sigma(+)-(1) Sigma(+) transition (63 300-69 350 cm(-1)) in the vacuum ultraviolet (vacuum UV) region was measured under jet-cooled conditions by using a tunable vacuum UV laser as an excitation light source and by monitoring the fragment S(S-1) atom. Due to sufficient vibrational and rotational cooling in a supersonic jet, a simple and distinct vibrational progression of the (1) Sigma(+)-(1) Sigma(+) band was recorded free from vibrational hot bands and the broadening by rotational structure. The autocorrelation function obtained from a Fourier transform of the PHOFEX spectra clearly exhibited recurrences with a period of 42 fs, corresponding to a period of the vibrational motion at the transition state along the direction perpendicular to the dissociation coordinate, This interpretation of the ultrafast motion in the transition-state region was supported by the wavepacket calculation on the ab initio PES obtained in the present study, which afforded a period of 48 fs for vibrational motion along the in-phase CO and CS stretching mode at the transition state on the ab initio PES. The distinct six peaks broadened due to the fast dissociation process were assigned to the transitions at the upsilon(TS) 0-5 levels, where upsilon(TS) represents a vibrational quantum number for the Feshbach resonances in the in-phase stretching mode at the transition state. For the upsilon(TS) = 0 peak, the narrowest width corresponding to the lifetime, tau(upsilon(TS)), of tau(0) = 133 fs was obtained. It was found that the dissociation lifetime first becomes shorter for a larger upsilon(TS), i.e., tau(1) = 44 fs and tau(2) = 27 fs, and then, the peak width becomes narrower for the higher vibrational states above upsilon(TS) = 2, with corresponding lifetimes of tau(3) = 47 fs and tau(4) = 44 fs. This deceleration of the dissociation rate for the larger upsilon(TS) states was interpreted as a result of trapping of a wave function in the in-phase stretching or the CO stretching vibrational motion suppressing the motion along the dissociation coordinate. All six main peaks in the PHOFEX spectra exhibited a characteristic asymmetric profile, originating from the interference between the zero-order discrete states for the in-phase stretching vibration at the transition state and the zero-order continuum states corresponding with the motion along the dissociation coordinate. In the main progression of the PHOFEX spectra, the reversal of the asymmetry direction was also observed. This q-reversal phenomenon was ascribed to the characteristic shape of the excited (1) Sigma(+) PES near the transition region which causes a phase shift in the wave functions in a narrow energy range.

    DOI: 10.1021/jp962423m

    Web of Science

  110. Photodissociating small polyatomic molecules in the VUV region: Resonances in the (1)Sigma(+)-(1)Sigma(+) band of OCS Reviewed

    K Yamanouchi, K Ohde, A Hishikawa, DM Neumark

    CHEMICAL REACTIONS AND THEIR CONTROL ON THE FEMTOSECOND TIME SCALE XXTH SOLVAY CONFERENCE ON CHEMISTRY   Vol. 101   page: 789 - 797   1997

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    Language:English   Publisher:JOHN WILEY & SONS INC  

    DOI: 10.1002/9780470141601.ch31

    Web of Science

  111. Radiative lifetime measurements of the B2∑+ state of BaH by laser spectroscopy Reviewed

    L. E. Berg, K. Ekvall, A. Hishikawa, S. Kelly

    Physica Scripta   Vol. 55 ( 3 ) page: 269 - 272   1997

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Royal Swedish Academy of Sciences  

    By applying laser resonance methods in the near infrared wavelength region around 900 nm, a time-resolved experiment has been performed on the low lying B 2∑+ state of barium hydride. The radiative lifetime is shown to vary with the rotational quantum number due to perturbations between the low lying A′ 2Δ, A 2∏ and B 2∑+ states. The following lifetime was obtained for the BaH molecule, where local perturbations are assumed to be negligible: τ(B 2∑+(ν′ = 0, J = 5.5)) = 125 ± 2 ns.

    DOI: 10.1088/0031-8949/55/3/003

    Scopus

  112. Laser spectroscopy of SrH. Time-resolved measurements of the A(2)Pi state Reviewed

    LE Berg, K Ekvall, A Hishikawa, S Kelly, C McGuinness

    CHEMICAL PHYSICS LETTERS   Vol. 255 ( 4-6 ) page: 419 - 424   1996.6

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    In the near-infrared and red wavelength region around 680-760 nm, the spectrum of the A(2) Pi-X(2) Sigma transition of gaseous SrH appears. By applying laser spectroscopic methods, a time-resolved experiment has been performed on the low-lying A(2) Pi state of strontium hydride. No local influences on the A(2) Pi state were found due to interactions with the low-lying A'(2) Delta state, as in the case of the BaH molecule. The following zero-pressure lifetime was obtained for the SrH molecule: tau(A(2) Pi(1/2) (upsilon'=0))=33.8+/-1.9 ns.

    DOI: 10.1016/0009-2614(96)00376-4

    Web of Science

  113. VUV photofragment excitation spectroscopy: Dynamics on dissociative potential surface of OCS Reviewed

    K Ohde, A Hishikawa, K Yamanouchi

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   Vol. 79   page: 433 - 436   1996.5

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    The measurements of the photofragment excitation (PHOFEX) spectrum of jet-cooled OCS were extended toward the 152.6 and 150.6 nm peaks in the (1) Sigma(+)-(1) Sigma(+) transition. The PHOFEX spectra were recorded by scanning the wavelength of a tunable vacuum ultraviolet (VU) photolysis laser while probing the S(S-1) product by a second laser. Due to the efficient cooling of the sample in the free-jet expansion and the high-resolving power of the VUV laser, the homogeneous broadening of the dissociative state was derived directly from the observed PHOFEX spectrum. Based on the measured peak width, the lifetimes (tau) of the dissociative states at 152.6 and 150.6 nm were determined to be tau approximate to 50 and 31 fs. The PHOFEX peaks were found to exhibit an asymmetric line profile, and a fitting to a Fano line formula led to the asymmetry parameters, q= -8.1(2) and -13.0(6), for the 152.6 and 150.6 nm peaks, indicating a considerable mixing of the continuum and discrete states in that particular energy region. On the basis of the determined lifetimes and q values, together with the corresponding values for the 154.5 nm peak, tau approximate to 140 fs and q = -3.5(9), the dissociation dynamics on the repulsive (1) Sigma(+) surface was inferred.

    DOI: 10.1016/0368-2048(96)02888-5

    Web of Science

  114. PHOTODISSOCIATION AND VIBRATIONAL DYNAMICS OF OCS IN THE VUV REGION Reviewed

    K YAMANOUCHI, K OHDE, A HISHIKAWA, CD PIBEL

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   Vol. 68 ( 9 ) page: 2459 - 2464   1995.9

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    The photofragment excitation (PHOFEX) spectrum of jet-cooled OCS was remeasured for the 154.5 nm peak in the (1) Sigma(+)-(1) Sigma(+) transition by scanning a tunable vacuum ultraviolet (VUV) laser wavelength in the deep VUV region and by probing the S(S-1) product with a second laser. Due to the efficient cooling of the sample in the free-jet expansion and the high-resolving power of the VUV laser, the homogeneous broadening of the dissociative state was derived directly from the observed PHOFEX spectrum. Based on the measured peak width, the lifetime (tau) of the dissociative state was determined to be tau congruent to 0.14 ps. The profile of the PHOFEX peak was found to be asymmetric and was fit to a Fano line profile to derive the value of the asymmetry parameter, q=-3.5(9), which indicates a considerable mixing of the continuum and discrete states in that particular energy region. A Fourier-transform analysis was also performed for the whole distinct absorption feature in the 160-140 nm region measured by McCarthy and Vaida [J. Phys. Chem., 92, 5875 (1988)], and the period of the vibrational motion on the dissociative potential-energy surface was derived to be 41 fs. Using these pieces of experimental evidence, the dissociation dynamics on the repulsive (1) Sigma(+) surface in the 154.5 nm region was inferred.

    DOI: 10.1246/bcsj.68.2459

    Web of Science

  115. MONTE-CARLO STUDY OF POPULATION AND ALIGNMENT RELAXATION BY TRAPPED LINE RADIATION Reviewed

    A HISHIKAWA, T FUJIMOTO, P ERMAN

    PHYSICAL REVIEW A   Vol. 52 ( 1 ) page: 189 - 196   1995.7

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    DOI: 10.1103/PhysRevA.52.189

    Web of Science

  116. ENERGY-DEPENDENT COLLISION CROSS-SECTION AS ESTIMATED FROM TEMPERATURE-DEPENDENT RATE COEFFICIENT - DISALIGNMENT OF EXCITED NEON ATOMS BY NEON COLLISIONS Reviewed

    Y ISHITANI, H ISHIDA, T KITAGAWA, A HISHIKAWA, T FUJIMOTO

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 26 ( 19 ) page: L671 - L675   1993.10

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    Laser-induced-fluorescence spectroscopy has been applied to a neon discharge plasma. A disalignment rate coefficient for 2p2 (Paschen notation; 2p5 3p configuration) atoms for neon atom collisions was determined at several atom temperatures (77-640 K). From the temperature dependence of the rate coefficient we estimate the cross section which explicitly depends on collision energy. It is found that the cross section has a positive energy dependence, which suggests that the OMEGA = 0 and 1 molecular potential curves correlating to the 2P2 State of neon are repulsive by about 100 cm-1 where these curves split by 10-20 cm-1.

    DOI: 10.1088/0953-4075/26/19/007

    Web of Science

  117. LIFETIME MEASUREMENTS OF EXCITED MOLECULAR-STATES USING A TI-SAPPHIRE LASER - RADIATIVE LIFETIMES OF THE A(2)PI,B(2)SIGMA(+), AND C(2)PI STATES OF BACL Reviewed

    LE BERG, A HISHIKAWA, A KARAWAJCZYK, T OLSSON

    JOURNAL OF MOLECULAR SPECTROSCOPY   Vol. 160 ( 2 ) page: 593 - 595   1993.8

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    Language:English   Publisher:ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS  

    DOI: 10.1006/jmsp.1993.1206

    Web of Science

  118. LIFETIME MEASUREMENTS OF EXCITED MOLECULAR-STATES USING A TI SAPPHIRE LASER RADIATIVE LIFETIMES OF THE A(2)PI, B(2)SIGMA(+) AND C(2)PI STATES OF BAF Reviewed

    LE BERG, T OLSSON, JC CHANTELOUP, A HISHIKAWA, P ROYEN

    MOLECULAR PHYSICS   Vol. 79 ( 4 ) page: 721 - 725   1993.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:TAYLOR & FRANCIS LTD  

    A time resolved experiment on the lowest lying states of barium fluoride has been performed by applying laser resonance methods in the near infrared and green-blue wavelength regions. The A2PI and B2SIGMA+ states have been examined using Ti:sapphire laser excitations in the 710-850 nm wavelength region. The C2PI state was examined using the 496.5 nm Ar+ laser line and the lifetime of this state was in accordance with earlier measurements. The lifetimes obtained for the BaF molecule were: A2PI3/2, 46.1 +/- 0.9 ns; B2SIGMA+, 41.7 +/- 0.3 ns.

    DOI: 10.1080/00268979300101571

    Web of Science

  119. LIFETIME MEASUREMENTS OF EXCITED MOLECULAR-STATES USING A TI-SAPPHIRE LASER - RADIATIVE LIFETIMES OF THE B(2)SIGMA+ STATE AND C(2)PI STATE OF BABR Reviewed

    LE BERG, K EKVALL, E HEDIN, A HISHIKAWA, A KARAWAJCZYK, S KELLY, T OLSSON

    CHEMICAL PHYSICS LETTERS   Vol. 209 ( 1-2 ) page: 47 - 51   1993.6

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    The barium bromide monohalide has been studied by using laser resonance methods in the near-infrared and green-blue wavelength regions. The low-lying B 2SIGMA+ state has been investigated in a time-resolved experiment using a Ti:sapphire laser operating around 900 nm. No influence on the radiative lifetime due to the B 2SIGMA interaction with the A'2DELTA-A 2PI complex was observed. The radiative lifetime of the C2PI state was examined using the 514.5 nm Ar+ laser line. The derived lifetime of this state was in agreement with earlier measurements. The following lifetimes were obtained for the BaBr molecule: B 2SIGMA+ 123.2 +/- 0.5 ns and C2PI(3/2)16.9+/-0.1 ns.

    DOI: 10.1016/0009-2614(93)87199-d

    Web of Science

  120. PREDISSOCIATION EFFECTS IN THE A2-DELTA AND B2-SIGMA- STATES OF CD Reviewed

    M DANIELSSON, P ERMAN, A HISHIKAWA, M LARSSON, E RACHLEWKALLNE, G SUNDSTROM

    JOURNAL OF CHEMICAL PHYSICS   Vol. 98 ( 12 ) page: 9405 - 9411   1993.6

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    Lifetimes have been measured for a large number of rotational levels of the A2DELTA and B2SIGMA-states in CD using the high frequency deflection technique. Four B-state levels are found to be influenced by predissociation by rotation which demands a lower value of the CD dissociation energy. The B state predissociations have also been studied using ab initio calculations. The A state levels above the dissociation limit are found to be weakly predissociated through interaction with the ground state continuum. The results are compared with earlier lifetime investigations of CH.

    DOI: 10.1063/1.464372

    Web of Science

  121. THE ELECTRONIC-TRANSITION MOMENT AND THE OSCILLATOR STRENGTH OF THE SIH+ A1-PI-X1-SIGMA+ TRANSITION Reviewed

    A HISHIKAWA, A KARAWAJCZYK

    JOURNAL OF MOLECULAR SPECTROSCOPY   Vol. 158 ( 2 ) page: 479 - 481   1993.4

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    DOI: 10.1006/jmsp.1993.1091

    Web of Science

  122. EXPERIMENTAL-OBSERVATION OF DISALIGNMENT EFFECTS IN RADIATION TRAPPING PROCESSES Reviewed

    P ERMAN, A HISHIKAWA

    PHYSICA SCRIPTA   Vol. 46 ( 4 ) page: 348 - 353   1992.10

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    Alignment effects at electron excitation measurements of atomic lifetimes have been studied at 20 keV energy using the High Frequency Deflection technique and a plastic polarizer. Disalignment associated with radiation trapping is observed directly for the first time. It has been pointed out that our previous results of the lifetime of the Ar 2p(i) levels might possibly have been influenced not only by radiation trapping itself but also by this "radiative disalignment". However, this influence has been found to be negligible thanks to small intrinsic alignment in almost all lines of noble gases investigated.

    DOI: 10.1088/0031-8949/46/4/006

    Web of Science

  123. INFLUENCE OF RADIATION TRAPPING ON THE POLARIZATION DEGREE OF THE HE-I 501.6 NM LINE IN COLLISION SPECTROSCOPY Reviewed

    A HISHIKAWA, H MIZUNO, M TANI, R OKASAKA

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 25 ( 16 ) page: 3419 - 3431   1992.8

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    The influence of radiation trapping on the polarization degree of the emission of the He I 501.6 nm line (3(1)P-2(1)S) is studied by experiments and a simulation. In the experiments, a particle (proton or electron) beam was injected into a helium gas cell. The accelerating energy was 100 keV for protons and 1.5, 2.5 and 5.0 keV for electrons. The polarization degree measured as a function of gas pressure showed a minimum at a certain gas pressure in accordance with results obtained by Hasselkamp et al. A Monte Carlo simulation method to treat the non-resonance line of the resonance state in a finite gas cell is presented. This simulation reproduces the minimum of the polarization degree as seen from experiments. We conclude that this minimum is caused by the asymmetry in the spatial distribution of atoms excited by collisions. We attempt to estimate a polarization degree not influenced by radiation trapping by fitting the simulated results to the experimental ones.

    DOI: 10.1088/0953-4075/25/16/004

    Web of Science

  124. The g-u interference oscillations observed in the emission cross sections and the optical polarizations in he+—he collisions Reviewed

    M. Tani, A. Hishikawa, R. Okasaka

    Journal of Physics D: Applied Physics   Vol. 24 ( 6 ) page: 1359 - 1376   1991.3

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    We have observed emission radiation from helium atoms excited in He+-He collisions by the direct and electron capture processes over the energy range 0.5-20 keV.The relative emission cross sections for transitions 21,3P-31,3S, 21,3S-31,3P and 21,3P-31,3Dhave been determined. Degrees of optical polarization have also been determined for theP- and D-state excitations. The emission cross section of the direct excitation and that ofthe electron capture excitation show oscillations against impact energy, which are inantiphase with each other. The polarization degrees for both processes are of nearly thesame magnitude and show weak oscillations in antiphase with each other. The oscillationsof the cross section and those of the polarization degree are in phase in some cases andin antiphase in other cases. These oscillations are interpreted as due to the interferencebetween the gerade and ungerade states of the helium quasimolecular ion. From theamplitude ratio and the phase correlation between the oscillations of the cross section andthose of the polarization degree we find that the predominant g-u interference pai r is nΠg-Πu. © IOP Publishing Ltd.

    DOI: 10.1088/0953-4075/24/6/022

    Scopus

  125. THE G-U INTERFERENCE OSCILLATIONS OBSERVED IN THE EMISSION CROSS-SECTIONS AND THE OPTICAL POLARIZATIONS IN HE+-HE COLLISIONS Reviewed

    M TANI, A HISHIKAWA, R OKASAKA

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   Vol. 24 ( 6 ) page: 1359 - 1376   1991.3

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    We have observed emission radiation from helium atoms excited in He+-He collisions by the direct and electron capture processes over the energy range 0.5-20 keV. The relative emission cross sections for transitions 2(1,3)P-3(1,3)S, 2(1,3)S-3(1,3)P and 2(1,3)P-3(1,3)D have been determined. Degrees of optical polarization have also been determined for the P- and D-state excitations. The emission cross section of the direct excitation and that of the electron capture excitation show oscillations against impact energy, which are in antiphase with each other. The polarization degrees for both processes are of nearly the same magnitude and show weak oscillations in antiphase with each other. The oscillations of the cross section and those of the polarization degree are in phase in some cases and in antiphase in other cases. These oscillations are interpreted as due to the interference between the gerade and ungerade states of the helium quasimolecular ion. From the amplitude ratio and the phase correlation between the oscillations of the cross section and those of the polarization degree we find that the predominant g-u interference pairs is PI-g-PI-u.

    DOI: 10.1088/0953-4075/24/6/022

    Web of Science

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Books 2

  1. 化学便覧基礎編(改訂6版) Reviewed

    菱川明栄( Role: Contributor ,  15.1 原子スペクトル)

    丸善出版  2021.1  ( ISBN:978-4-621-30521-8

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    Total pages:1534   Responsible for pages:6.5   Language:Japanese Book type:Dictionary, encyclopedia

  2. 原子分子物理学ハンドブック

    市川行和,大谷俊介( Role: Joint author)

    朝倉書店  2012.4  ( ISBN:978-4-254-13105-5

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    Language:Japanese

MISC 97

  1. On the measurement of statistical dynamics using the method of Coulomb explosion imaging International coauthorship

    Tomoyuki Endo, Simon P Neville, Vincent Wanie, Samuel Beaulieu, Chen Qu, Philippe Lassonde, Bruno E Schmidt, Hikaru Fujise, Mizuho Fushitani, Akiyoshi Hishikawa, Paul L Houston, Joel M Bowman, Michael S Schuurman, François Légaré, Heide Ibrahim

    AIP Conference Proceedings   Vol. 2343 ( 1 ) page: 020006   2021.3

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    Language:English   Publishing type:Research paper, summary (international conference)  

    DOI: 10.1063/5.0047930

  2. Capturing Roaming Fragments in Real Time: A Molecular Road Movie International coauthorship

    Tomoyuki Endo, Simon P Neville, Vincent Wanie, Samuel Beaulieu, Chen Qu, Jude Deschamps, Philippe Lassonde, Bruno E Schmidt, Hikaru Fujise, Mizuho Fushitani, Akiyoshi Hishikawa, Paul L Houston, Joel M Bowman, Michael S Schuurman, François Légaré, Heide Ibrahim

    The 22nd International Conference on Ultrafast Phenomena 2020     page: Th4A. 1   2020.11

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    Language:English   Publishing type:Article, review, commentary, editorial, etc. (international conference proceedings)  

  3. Multielectron-Ion Coincidence Spectroscopy of Xe in EUV Laser Fields: Observation of Nonlinear Formation of Double-Core-Hole States Invited Reviewed

    FUSHITANI Mizuho, MATSUDA Akitaka, HIKOSAKA Yasumasa, HISHIKAWA Akiyoshi

      Vol. 25   page: 272 - 277   2020

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    Authorship:Last author   Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (bulletin of university, research institution)  

  4. 強レーザー場トンネル現象で分子の光励起の様子を可視化 (特集 物理科学,この1年) -- (原子・分子物理,量子エレクトロニクス)

    菱川 明栄

    パリティ = Parity : 物理科学雑誌   Vol. 32 ( 1 ) page: 8 - 10   2017.1

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    Language:Japanese   Publisher:丸善出版  

    CiNii Article

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  5. Development of Electron-Ion Coincidence Spectroscopy for XFEL

    Matsuda Akitaka, Fushitani Mizuho, Endo Tomoyuki, Toida Yuto, Hikosaka Yasumasa, Hishikawa Akiyoshi

    SPring-8/SACLA Research Report   Vol. 5 ( 2 ) page: 291 - 294   2017

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    DOI: 10.18957/rr.5.2.291

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  6. Ultrafast Multiphoton Manipulation of Quantum States by Intense Laser Pulses

    FUSHITANI Mizuho, HISHIKAWA Akiyoshi

    The Review of Laser Engineering   Vol. 45 ( 8 ) page: 493 - 493   2017

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    Coherent light-matter interaction drives a variety of interesting processes in a quantum system. Rabioscillation is one such process offering a periodic population transfer between quantum states in anultrashort time scale. Here we demonstrate a robust and simple scheme to achieve femtosecond twophotonRabi oscillations by intense NIR laser pulses, using excited He atoms prepared by EUV-FEL.The extension to multiphoton regime will expand the applicability to highly excited or dipole-forbiddenstates.

    DOI: 10.2184/lsj.45.8_493

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  7. Ultrafast Reaction Imaging by Intense Laser Pulses

      Vol. 66 ( 5 ) page: 170 - 180   2017

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  8. XFEL Auger Electron Sideband Measurements by Near-Infrared Strong Laser Pulses

    Fushitani Mizuho, Matsuda Akitaka, Endo Tomoyuki, Toida Yuto, Hishikawa Akiyoshi, Hikosaka Yasumasa

    SPring-8/SACLA Research Report   Vol. 4 ( 2 ) page: 344 - 347   2016

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    DOI: 10.18957/rr.4.2.344

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  9. 22pAE-12 Asymmetric Coulomb explosion of CO_2 in phase controlled two-color intense laser fields

    Endo T., Fujise H., Kawachi Y., Ishihara A., Hishikawa A.

    Meeting Abstracts of the Physical Society of Japan   Vol. 71 ( 0 ) page: 820 - 820   2016

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    DOI: 10.11316/jpsgaiyo.71.1.0_820

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  10. 22pAE-11 Ultrafast Photoelectron Spectroscopy of N_2 Rydberg Wavepacket Dynamics by EUV Laser High Harmonics

    Fushitani M., Toida Y., Legare Francois, Hishikawa A.

    Meeting Abstracts of the Physical Society of Japan   Vol. 71 ( 0 ) page: 819 - 819   2016

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    DOI: 10.11316/jpsgaiyo.71.1.0_819

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  11. 17pAA-7 Observation of asymmetric molecular orbital of NO by phase-controlled two-color intense laser pulses

    Endo T., Ishihara A., Matsuda A., Fushitani M., Hishikawa A.

    Meeting Abstracts of the Physical Society of Japan   Vol. 70 ( 0 ) page: 516 - 516   2015

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    DOI: 10.11316/jpsgaiyo.70.2.0_516

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  12. Ultarafast Photoelectron Spectroscopy of Molecular Wavepacket Dynamics by Laser High-Order Harmonics

    FUSHITANI Mizuho, HISHIKAWA Akiyoshi

    The Review of Laser Engineering   Vol. 43 ( 12 ) page: 818 - 818   2015

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    Laser high-order harmonics in the extreme ultraviolet (EUV) and soft X-ray region serve as a uniquetool to study ultrafast molecular dynamics associated with valence or inner-shell electron excitations.The harmonics are often obtained as a train of pulses, which result in a spectrum with a comb consistingof the odd harmonic orders. However, it is often the case that isolated pulses rather than pulse trains arepreferred in the conventional pump-probe spectroscopy, to avoid signal overlaps associated with differentharmonic orders. Here we review our approach for the single-order harmonics generation in EUV byusing dielectric multilayer mirrors and metal foils, and the application to photoelectron spectroscopy onwavepacket dynamics of simple molecules such as Br2, I2 and N2.

    DOI: 10.2184/lsj.43.12_818

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  13. 27pTM-7 Nonresonant EUV-UV two-color two-photon ionization of He atoms

    Fushitani M., Hikosaka Y., Matsuda A., Endo T., Shigemasa E., Nagasono M., Sato T., Togashi T., Hishikawa A.

    Meeting Abstracts of the Physical Society of Japan   Vol. 69 ( 0 ) page: 182 - 182   2014

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    DOI: 10.11316/jpsgaiyo.69.1.2.0_182_1

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  14. 27pEB-10 Ionization processes of polarized He(2^1P) atoms in intense laser fields

    Fushitani M., Matsuda A., Endo T., Toida Y., Morishita T., Nagasono M., Togashi T., Hikosaka Y., Hishikawa A.

    Meeting Abstracts of the Physical Society of Japan   Vol. 68 ( 0 ) page: 215 - 215   2013

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    DOI: 10.11316/jpsgaiyo.68.1.2.0_215_4

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  15. Polarization dependence in multiphoton ionization processes of polarized He(2^1P) atoms

    Fushitani M., Matsuda A., Endo T., Toida Y., Morishita T., Nagasono M., Togashi T., Hikosaka Y., Hishikawa A.

    Meeting Abstracts of the Physical Society of Japan   Vol. 68 ( 0 ) page: 170 - 170   2013

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    DOI: 10.11316/jpsgaiyo.68.2.2.0_170_2

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  16. 27pEB-6 Pulse duration dependence of three-photon double excitation of helium by intense extreme-ultraviolet pulses

    Morishita Toru, Liu Chien-Nan, Hishikawa Akiyoshi

    Meeting Abstracts of the Physical Society of Japan   Vol. 68 ( 0 ) page: 214 - 214   2013

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    DOI: 10.11316/jpsgaiyo.68.1.2.0_214_4

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  17. 偏極He原子の強レーザー場イオン化におけるコヒーレント2光子共鳴過程の観測

    伏谷瑞穂, 伏谷瑞穂, 松田晃孝, 遠藤友随, 樋田裕斗, 森下亨, 永園充, 富樫格, 彦坂泰正, 彦坂泰正, 菱川明栄, 菱川明栄

    分子科学討論会講演プログラム&amp;要旨(Web)   Vol. 7th   page: ROMBUNNO.2A17 (WEB ONLY)   2013

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  18. Nonlinear Processes of Atoms in Intense EUV Free-Electron Laser Fields

    Fushitani Mizuho, Hikosaka Yasumasa, Hishikawa Akiyoshi

    Butsuri   Vol. 68 ( 12 ) page: 794 - 801   2013

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    The advances in free electron laser (FEL) technology allow us to generate intense laser fields in extreme ultraviolet (EUV) and X-ray. Recent studies show that responses of materials to such high-frequency intense laser fields are inherently different from those observed in visible and infrared. In this reveiw, we discuss current progresses in intense laser field physics in EUV and X-ray, especially by focussing on non-linear responses of isolated atoms.

    DOI: 10.11316/butsuri.68.12_794

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  19. 数サイクル強レーザー場におけるNO分子のイオン化異方性:π‐σ軌道遷移の効果

    遠藤友随, 伏谷瑞穂, 松田晃孝, 安池智一, 森下亨, 菱川明栄

    分子科学討論会講演プログラム&amp;要旨(Web)   Vol. 7th   page: ROMBUNNO.2P017 (WEB ONLY)   2013

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  20. Ultrafast Spectroscopy Using Single-Order Laser High-Order Harmonics in EUV

    FUSHITANI Mizuho, MATSUDA Akitaka, HISHIKAWA Akiyoshi

      Vol. 61 ( 3 ) page: 98 - 100   2012.6

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  21. Single-shot photoelectron spectroscopy of multiphoton ionization of atoms irradiated with EUV-FEL pulses

    HIKOSAKA Yasumasa, FUSHITANI Mizuho, HISHIKAWA Akiyoshi

    しょうとつ(Web)   Vol. 9 ( 1 ) page: 5 - 10   2012

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    Multiphoton ionization is a typical nonlinear response of atoms in intense EUV laser fields. Single-shot photoelectron spectroscopy utilizing with a magnetic-bottle-type electron spectroscopic technique is a useful means to study the details of multiphoton multiple ionization processes. We present that the method enables us to monitor the fluctuation of SASE-FEL spectra and to derive photon energy dependence of the multiphoton multiple ionization processes precisely.

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  22. 27aAB-2 Energy correlation between photoelectrons in Xe double ionization in intense laser fields

    Matsuda Akitaka, Fushitani Mizuho, Hikosaka Yasumasa, Eland John H.D., Hishikawa Akiyoshi

    Meeting Abstracts of the Physical Society of Japan   Vol. 67 ( 0 ) page: 227 - 227   2012

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    DOI: 10.11316/jpsgaiyo.67.1.2.0_227_2

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  23. 27aAB-1 Fragment anisotropy on dissociative ionization of electronically excited NO in few-cycle intense laser fields

    Endo Tomoyuki, Fushitani Mizuho, Matsuda Akitaka, Hishikawa Akiyoshi

    Meeting Abstracts of the Physical Society of Japan   Vol. 67 ( 0 ) page: 227 - 227   2012

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    DOI: 10.11316/jpsgaiyo.67.1.2.0_227_1

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  24. 偏極He(2<sup>1</sup>P)原子の強レーザー場イオン化ダイナミクス

    伏谷瑞穂, 伏谷瑞穂, 松田晃孝, 遠藤友随, 樋田裕斗, 永園充, 富樫格, 彦坂泰正, 彦坂泰正, 菱川明栄, 菱川明栄

    分子科学討論会講演プログラム&amp;要旨(Web)   Vol. 6th   page: ROMBUNNO.4P005 (WEB ONLY)   2012

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  25. 励起状態NOの解離性イオン化過程におけるフラグメント空間異方性:軌道対称性の効果

    遠藤友随, 伏谷瑞穂, 松田晃孝, 菱川明栄

    分子科学討論会講演プログラム&amp;要旨(Web)   Vol. 6th   page: ROMBUNNO.3A06 (WEB ONLY)   2012

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  26. Real-Time Reaction Probing by Laser Coulomb Explosion Imaging

    HISHIKAWA Akiyoshi

    The Review of Laser Engineering   Vol. 40 ( 10 ) page: 745 - 745   2012

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    Molecules exposed to few-cycle intense laser fields (> 10<sup>14</sup> W/cm<sup>2</sup>) undergo a rapid bond breakingprocess called Coulomb explosion. Since the momenta of the resultant fragment ions reflect thegeometrical structure of the target molecule, Coulomb explosion provides a direct access to theinstantaneous structure of molecules during chemical reaction. Combined with the pump-probe schemein ultrafast spectroscopy, Coulomb explosion imaging serves as a unique means to probe ultrafastmolecular reaction processes in real time. Here we review this novel approach in ultrafast spectroscopy,with the applications to ultrafast isomerization of deuterated acetylene dication (C<sub>2</sub>D<sub>2</sub><sup>2+</sup>).

    DOI: 10.2184/lsj.40.10_745

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  27. クーロン爆発イメージングによる超高速反応追跡 (特集 超高速レーザフロンティア研究--アト秒科学)

    菱川 明栄

    光アライアンス   Vol. 22 ( 11 ) page: 19 - 22   2011.11

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  28. 光のゆらぎで探る:自由電子レーザ場中の原子--シングルショット光電子分光によるアプローチ (特集 ゆらぎ)

    伏谷 瑞穂, 菱川 明栄, 彦坂 泰正

    光アライアンス   Vol. 22 ( 10 ) page: 25 - 28   2011.10

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  29. 25aGL-8 Time-resolved EUV-UV photoelectron spectroscopy of rare gas atoms by FEL synchronized with optical laser pulses

    Fushitani Mizuho, Ohashi Haruhiko, Kimura Hiroaki, Senba Yasunori, Yabashi Makina, Ishikawa Tetsuya, Hikosaka Yasumasa, Matsuda Akitaka, Tseng Chien-Ming, Hishikawa Akiyoshi, Shigemasa Eiji, Nagasono Mitsuru, Tono Kensuke, Togashi Tadashi

    Meeting Abstracts of the Physical Society of Japan   Vol. 66 ( 0 ) page: 160 - 160   2011

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    DOI: 10.11316/jpsgaiyo.66.1.2.0_160_4

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  30. FEL同期レーザーを用いた希ガスの時間分解シングルショット光電子分光

    伏谷瑞穂, 伏谷瑞穂, 彦坂泰正, 彦坂泰正, 松田晃孝, 松田晃孝, 遠藤友随, 繁政英治, 繁政英治, 永園充, 佐藤堯洋, 登野健介, 富樫格, 大橋治彦, 大橋治彦, 仙波泰徳, 矢橋牧名, 石川哲也, 菱川明栄, 菱川明栄, 菱川明栄

    分子科学討論会講演プログラム&amp;要旨(Web)   Vol. 5th   page: ROMBUNNO.4P014 (WEB ONLY)   2011

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  31. 25aGL-9 Non-sequential multiphoton double ionization of Xe in intense laser fields studied by electron correlation measurement

    Matsuda Akitaka, Tseng Chien-Ming, Fushitani Mizuho, Hikosaka Yasumasa, Eland Eland John H. D., Hishikawa Akiyoshi

    Meeting Abstracts of the Physical Society of Japan   Vol. 66 ( 0 ) page: 161 - 161   2011

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    DOI: 10.11316/jpsgaiyo.66.1.2.0_161_1

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  32. Multi-photon multiple ionization of atoms irradiated with EUV SASE-FEL pulses

    HIKOSAKA Yasumasa, FUSHITANI Mizuho, HISHIKAWA Akiyoshi

      Vol. 23 ( 5 ) page: 291 - 294   2010.9

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  33. 25aRH-12 Multihphoton double ionization of Ar in intense EUV laser fields studied by shot-to-shot photoelectron spectroscopy

    Fushitani Mizuho, Ohashi Haruhiko, Kimura Hiroaki, Senba Yasunori, Yabashi Makina, Ishikawa Tetsuya, Hikosaka Yasumasa, Matsuda Akitaka, Tseng Chien-Ming, Hishikawa Akiyoshi, Shigemasa Eiji, Nagasono Mitsuru, Tono Kensuke, Togashi Tadashi

    Meeting Abstracts of the Physical Society of Japan   Vol. 65 ( 0 ) page: 147 - 147   2010

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    DOI: 10.11316/jpsgaiyo.65.2.2.0_147_2

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  34. Visualization of intramolecular hydrogen migration by coulomb explosion imaging

    Journal of Japan Laser Processing Society   Vol. 15 ( 3 ) page: 196 - 199   2008.7

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  35. アト秒ダイナミクス (2007年の成果の総まとめ 特集:物理科学,この1年) -- (原子・分子物理,量子エレクトロニクス)

    菱川 明栄

    パリティ   Vol. 23 ( 1 ) page: 13 - 15   2008.1

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  36. 24aQD-9 Dissociative ionization of molecules in intense laser fields studied by electron-ion coincidence imaging

    Matsuda Akitaka, Fushitani Mizuho, Hishikawa Akiyoshi

    Meeting Abstracts of the Physical Society of Japan   Vol. 63 ( 0 ) page: 163 - 163   2008

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    DOI: 10.11316/jpsgaiyo.63.1.2.0_163_2

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  37. 軟X線強光子場におけるH<sub>2</sub>の解離性イオン過程

    星名賢之助, 菱川明栄, 佐甲徳栄, 山内薫, 高橋栄治, 鍋川康夫, 緑川克美

    原子衝突研究協会研究会講演概要集   Vol. 30th   page: 41 - 42   2005.8

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  38. 軟X線強光子場におけるH<sub>2</sub>およびD<sub>2</sub>の解離性イオン化機構

    星名賢之助, 菱川明栄, 佐甲徳栄, 山内薫, 高橋栄治, 鍋川康夫, 緑川克美

    化学反応討論会講演要旨集   Vol. 21st   page: 56 - 57   2005.6

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  39. 高強度超短パルス軟X線高調波による多原子分子の光イオン化

    星名賢之助, 菱川明栄, 佐甲徳栄, 古川裕介, 山内薫, 鍋川康夫, 高橋栄治, 長谷川宗良, 緑川克美

    応用物理学関係連合講演会講演予稿集   Vol. 52nd ( 3 ) page: 1235   2005.3

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  40. Introduction to Molecular Spectroscopy

    HISHIKAWA Akiyoshi

    Journal of Plasma and Fusion Research   Vol. 80 ( 9 ) page: 742 - 748   2004.9

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    The structures of rotational and vibrational energy levels and the term symbols to classify different electronic states are described for diatomic molecules. Different classes of parity, (+/&minus;), (e/f) and (s/a), associated with each rovibronic level are discussed. The transition probability, the Franck-Condon factors, the H&ouml;nl-London factors and the transition moments of electronic transitions and their selection rules are described.

    DOI: 10.1585/jspf.80.742

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    Other Link: http://dl.ndl.go.jp/info:ndljp/pid/10455609

  41. 軟X線領域の強光子場と分子の相互作用:H<sub>2</sub>,D<sub>2</sub>の解離性イオン化

    星名賢之助, 菱川明栄, 佐甲徳栄, 山内薫, 高橋栄治, 鍋川康夫, 緑川克美

    分子構造総合討論会講演要旨集(CD-ROM)   Vol. 2004   page: 3P085   2004.9

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  42. 平成14年度理化学研究所・日本分光学会装置部会合同シンポジウム「超短パルス電子線・X線技術の現状と新展開」報告

    菱川 明栄

    分光研究 = Journal of the spectroscopical research of Japan   Vol. 52 ( 1 ) page: 36 - 36   2003.2

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    DOI: 10.5111/bunkou.52.36

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  43. Coulomb explosion dynamics of N_2O in intense laser fields probed by coincidence momentum imaging

    Ueyama M., Hishikawa A., Hasegawa H., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 58 ( 0 ) page: 152 - 152   2003

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    DOI: 10.11316/jpsgaiyo.58.1.2.0_152_3

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  44. Mesoscopic Coulomb explosion of triatomic molecules in intense laser fields

    Hishikawa A., Hasegawa H., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 58 ( 0 ) page: 152 - 152   2003

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    DOI: 10.11316/jpsgaiyo.58.1.2.0_152_4

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  45. コインシデンス運動量画像法によるアセトニトリルの強光子場中水素マイグレーション

    土井杏子, 長谷川宗良, 菱川明栄, 山内薫

    分子構造総合討論会講演要旨集   Vol. 2002   page: 702   2002.10

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  46. メソスコピック空間における強光子場中CS<sub>2</sub>の3体クーロン爆発過程

    菱川明栄, 長谷川宗良, 山内薫

    分子構造総合討論会講演要旨集   Vol. 2002   page: 76   2002.10

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  47. コインシデンス運動量画像法による強光子場中CS<sub>2</sub>の相関核ダイナミクス

    長谷川宗良, 菱川明栄, 山内薫

    分子構造総合討論会講演要旨集   Vol. 2002   page: 75   2002.10

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  48. アセトニトリルの強光子場中水素マイグレーション コインシデンス運動量画像法によるアプローチ

    土井杏子, 長谷川宗良, 菱川明栄, 山内薫

    光化学討論会講演要旨集   Vol. 2002   page: 363   2002.9

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  49. 強光子場中CS<sub>2</sub>の光反応追跡 コインシデンス運動量画像法によるアプローチ

    長谷川宗良, 土井杏子, 菱川明栄, 山内薫

    光化学討論会講演要旨集   Vol. 2002   page: 313   2002.9

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  50. コインシデンス運動量画像法による強光子場中CS<sub>2</sub>の核運動相関

    長谷川宗良, 菱川明栄, 山内薫

    原子衝突研究協会研究会講演概要集   Vol. 27th   page: 75   2002.8

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  51. コインシデンス運動量画像法による強光子場中の多原子分子ダイナミクス

    長谷川宗良, 土井杏子, 菱川明栄, 山内薫

    化学反応討論会講演要旨集   Vol. 18th   page: 111   2002.6

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  52. 強光子場中におけるCS<sub>2</sub>の配向と構造変形 光子場強度依存性

    星名賢之助, 海尻彩, 菱川明栄, 山内薫

    化学反応討論会講演要旨集   Vol. 18th   page: 109   2002.6

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  53. 強光子場中CS<sub>2</sub>の単一分子内核相関ダイナミクス

    長谷川宗良, 土井杏子, 菱川明栄, 山内薫

    化学反応討論会講演要旨集   Vol. 18th   page: 64 - 65   2002.6

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  54. Dissociative Ionization Processes of Highly Excited Molecules: An Approach using Higher-Order Harmonics in Extreme Ultraviolet Region.

    福田祐仁, 岩前敦, 古川裕介, 星名賢之助, 菱川明栄, 山内薫

    日本化学会講演予稿集   Vol. 81st ( 1 ) page: 312   2002.3

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  55. Real-time probing of alignment and deformation of molecules in ns pulsed laser fields.

    星名賢之助, 菱川明栄, 岩崎純史, 海尻彩, 山内薫

    日本化学会講演予稿集   Vol. 81st ( 1 ) page: 317   2002.3

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  56. 24pXL-1 Coincidence imaging measurements of CSZ in intense laser fields by position sensitive detector

    Hasegawa Hirokazu, Doi Kyoko, Hishikawa Akiyoshi, Yamanouchi Kaoru

    Meeting Abstracts of the Physical Society of Japan   Vol. 57 ( 0 ) page: 124 - 124   2002

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    DOI: 10.11316/jpsgaiyo.57.1.2.0_124_2

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  57. Probing of Coulomb explosion Processes of CS2 in intense laser fields by coincidence momentum imaging

    Hasegawa Hirokazu, Doi Kyoko, Hishikawa Akiyoshi, Yamanouchi Kaoru

    Meeting Abstracts of the Physical Society of Japan   Vol. 57 ( 0 ) page: 123 - 123   2002

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    DOI: 10.11316/jpsgaiyo.57.2.2.0_123_4

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  58. Photodissociation Processes of Polyatomic Molecules by Ultrashort-Pulsed XUV Light.

    福田祐仁, 岩前敦, 穂坂綱一, 星名賢之助, 菱川明栄, 山内薫

    日本原子力研究所JAERI-Conf     page: 288 - 291   2001.10

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  59. Real-time dynamics of CS2 in intense nanosecond laser fields: Alignment and structural deformation.

    岩崎純史, 菱川明栄, 星名賢之助, 山内薫

    分子構造総合討論会講演要旨集   Vol. 2001   page: 449   2001.9

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  60. Generation of higher-order harmonics by ultrashort pulsed laser and its application to photochemistry.

    福田祐仁, 岩前敦, 穂坂綱一, 星名賢之助, 菱川明栄, 山内薫

    光化学討論会講演要旨集   Vol. 2001   page: 391   2001.9

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  61. 強光子場中CS<sub>2</sub>の配向と構造変形の実時間追跡

    岩崎純史, 菱川明栄, 星名賢之助, 山内薫

    原子衝突研究協会研究会講演概要集   Vol. 26th   page: 39   2001.8

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  62. Dissociative ionization dynamics of molecules by extreme ultraviolet laser light.

    福田祐二, 岩前敦, 穂坂綱一, 星名賢之助, 菱川明栄, 山内薫

    化学反応討論会講演要旨集   Vol. 17th   page: 58 - 59   2001.5

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  63. 平成12年度理化学研究所・日本分光学会装置部会合同シンポジウム「強光子場の科学とその応用」報告

    菱川 明栄

    分光研究 = Journal of the spectroscopical research of Japan   Vol. 50 ( 2 ) page: 76 - 77   2001.4

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    DOI: 10.5111/bunkou.50.76

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  64. Dissociative Ionization Spectroscopy by Higher-Order Harmonics in the Extreme Ultraviolet Region.

    福田祐仁, 岩前敦, 穂坂綱一, 星名賢之助, 菱川明栄, 山内薫

    日本化学会講演予稿集   Vol. 79th ( 1 ) page: 229   2001.3

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  65. Molecules in Intense Light Fields - Orientation, Geometrical Deformation, and Explosion -

    HISHIKAWA Akiyoshi, YAMANOUCHI Kaoru

    Butsuri   Vol. 56 ( 1 ) page: 2 - 7   2001.1

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    DOI: 10.11316/butsuri1946.56.2

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  66. Molecular alignment and structural deformation in intense laser fields.

    Hishikawa A., Iwasaki A., Hoshina K., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 56 ( 0 ) page: 83 - 83   2001

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    DOI: 10.11316/jpsgaiyo.56.2.2.0_83_2

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  67. Coulomb explosion of acetylene in intense laser fields

    Hasegawa H., Hishikawa A., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 56 ( 0 ) page: 124 - 124   2001

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    DOI: 10.11316/jpsgaiyo.56.1.2.0_124_1

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  68. The Renner-Teller interaction in the X.PI. state of OCS+.

    古川裕介, 福田祐仁, 星名賢之助, 菱川明栄, 山内薫

    分子構造総合討論会講演要旨集   Vol. 2000   page: 616   2000.9

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  69. 強光子場中の原子分子ダイナミクス

    菱川 明栄

    原子衝突サーキュラー : 原子衝突研究協会会報   ( 192 ) page: 3 - 5   2000.9

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  70. Ultrafast Molecular Dynamics in Intense Laser Fields

    HISHIKAWA Akiyoshi, YAMANOUCH Kaoru

    Journal of the Spectroscopical Society of Japan   Vol. 49 ( 2 ) page: 62 - 71   2000.4

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    DOI: 10.5111/bunkou.49.62

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  71. 強光子場中の分子ダイナミクス (超高速化学ダイナミクス--フェムト・ピコ秒領域の化学) -- (超短パルスレーザー場と化学過程)

    菱川 明栄, 山内 薫

    季刊化学総説   ( 44 ) page: 232 - 243   2000.3

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  72. Tandem-type mass spectroscopy of molecular ions in intense laser fields

    Itakura R., Watanabe J., Hishikawa A., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 55 ( 0 ) page: 97 - 97   2000

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  73. Photodissociation of O_2^+ in intense laser fields : Formation of quartet dressed states

    Hishikawa A., Liu S., Iwasaki A., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 55 ( 0 ) page: 97 - 97   2000

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    DOI: 10.11316/jpsgaiyo.55.2.2.0_97_4

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  74. Coulomb explosion dynamics of molecules aligned in intense laser fields

    Iwasaki A., Hishikawa A., Yamanouchi K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 55 ( 0 ) page: 97 - 97   2000

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    DOI: 10.11316/jpsgaiyo.55.2.2.0_97_3

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  75. 多原子分子の広範囲振動準位構造の高分解能測定 アセチレンの非調和共鳴ダイナミクス

    星名賢之助, 岩崎純史, 河野光彦, 菱川明栄, 山内薫

    日本物理学会講演概要集   Vol. 53 ( 2 ) page: 343   1998.9

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  76. 高分解能DF分光法によるアセチレンの高振動励起状態

    星名賢之助, 岩崎純史, 河野光彦, 菱川明栄, 山内薫

    分子構造総合討論会講演要旨集   Vol. 1998   page: 256   1998.9

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  77. CO<sub>2</sub>およびCS<sub>2</sub>の強光子場中ドレスト分子ダイナミクスMRMI法によるアプローチ

    菱川明栄, 岩前敦, 星名賢之助, 河野光彦, 山内薫

    分子構造総合討論会講演要旨集   Vol. 1998   page: 576   1998.9

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  78. アセチレンのIR‐VUV二重共鳴光解離分光

    河野光彦, 岩崎純史, 星名賢之助, 菱川明栄, 山内薫

    分子構造総合討論会講演要旨集   Vol. 1998   page: 454   1998.9

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  79. 単一経路MRMI法によるNOの強光子場中ダイナミクス

    岩前敦, 菱川明栄, 星名賢之助, 河野光彦, 山内薫

    分子構造総合討論会講演要旨集   Vol. 1998   page: 16   1998.9

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  80. ドレスト分子ダイナミクス NO<sub>2</sub>の強光子場誘起大振幅変角運動

    菱川明栄, 岩前敦, 星名賢之助, 河野光彦, 山内薫

    分子構造総合討論会講演要旨集   Vol. 1998   page: 17   1998.9

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  81. Coulomb explosion of NO molecule in the intense laser field studied by the mass-resolved momentum imaging (MRMI) method.

    岩前敦, 菱川明栄, 星名賢之助, 河野光彦, 山内薫

    化学反応討論会講演要旨集   Vol. 14th   page: 133   1998.5

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  82. IVR dynamics of acetylene: A new approach by using IR-UV excitation dispersed fluorescence spectrum.

    星名賢之助, 河野光彦, 岩前敦, 菱川明栄, 山内薫

    化学反応討論会講演要旨集   Vol. 14th   page: 97   1998.5

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  83. Coulomb Explosion Dynamics of Polyatomic Molecules in Intense Laser Field by Mass-Resolved Momentum Imaging.

    菱川明栄, 岩前敦, 星名賢之助, 河野光彦, 山内薫

    化学反応討論会講演要旨集   Vol. 14th   page: 27   1998.5

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  84. Mass-resolved momentum imaging(MRMI) of molecular Coulomb explosion in an intense laser-field.

    菱川明栄, 岩前敦, 星名賢之助, 河野光彦, 山内薫

    日本化学会講演予稿集   Vol. 74th ( 1 ) page: 391   1998.3

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  85. Femtosecond dynamics of polyatomic molecules in an intense field by the MRMI technique.

    菱川明栄, 星名賢之助, 岩前敦, 河野光彦, 山内薫

    日本化学会講演予稿集   Vol. 74th ( 1 ) page: 392   1998.3

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  86. Aligment of NO in intense laser field by single-pathway MRMI method

    HISHIKAWA A., IWAMAE A., HOSHINA K., KONO M., YAMANOUCHI K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 53 ( 0 ) page: 874 - 874   1998

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    DOI: 10.11316/jpsgaiyo.53.2.4.0_874_2

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  87. Molecular Coulomb explosion in intense laser field studied by mass-resolved momentum imaging (MRMI) method

    HISIKAWA Akiyoshi, HOSHINA Kennosuke, IWAMAE Atsushi, KONO Mitsuhiko, YAMANOUCHI Kaoru

    Meeting Abstracts of the Physical Society of Japan   Vol. 53 ( 0 ) page: 769 - 769   1998

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    DOI: 10.11316/jpsgaiyo.53.1.4.0_769_3

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  88. Molecular Coulomb explosion in an intense laser field studied by mass-resolved momentum imaging (MRMI) method

    HISIKAWA Akiyoshi, IWAMAE Atsushi, HOSHINA Kennosuke, KONO Mitsuhiko, YAMANOUCHI Kaoru

    Meeting Abstracts of the Physical Society of Japan   Vol. 53 ( 0 ) page: 769 - 769   1998

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    DOI: 10.11316/jpsgaiyo.53.1.4.0_769_2

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  89. High-resolution measurements of vibrational structure of polyatomic molecule in wide energy range : Anharmonic resonances of acetylene

    HOSHINA Kennosuke, IWASAKI Atsushi, KONO Mitsuhiko, HISHIKAWA Akiyoshi, YAMANOUCHI Kaoru

    Meeting Abstracts of the Physical Society of Japan   Vol. 53 ( 0 ) page: 343 - 343   1998

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    DOI: 10.11316/jpsgaiyo.53.2.2.0_343_1

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  90. Ultrafast photodissociation of OCS by tunable VUV-VUV pump-probe spectroscopy

    ITAKURA Ryuji, HISHIKAWA Akiyoshi, YAMANOUCHI Kaoru

    Meeting Abstracts of the Physical Society of Japan   Vol. 53 ( 0 ) page: 344 - 344   1998

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    DOI: 10.11316/jpsgaiyo.53.2.2.0_344_3

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  91. Molecular dressed-state dynamics in intense laser field : Ultrafast structural deformation of NO_2

    HISHIKAWA A., IWAMAE A., HOSHINA K., KONO M., YAMANOUCHI K.

    Meeting Abstracts of the Physical Society of Japan   Vol. 53 ( 0 ) page: 874 - 874   1998

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    DOI: 10.11316/jpsgaiyo.53.2.4.0_874_3

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  92. Control of Photochemical Reaction in Femtosecond Time Scale.

    菱川明栄, 河野光彦, 星名賢之助, 岩前敦, LIU S, 佐甲徳栄, 佐藤弘一, 板倉隆二, 山内薫

    分子構造総合討論会講演要旨集   Vol. 1997   page: 160   1997.10

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  93. 希ガスクラスタ-の内殻励起スペクトル

    菱川 明栄

    化学と工業 = Chemistry and chemical industry   Vol. 48 ( 10 ) page: 1265 - 1265   1995.10

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  94. 31a-F-2 Collisional disalignment and molecular potentials

    Hishikawa A, Yamamoto A, Wakabayashi T, Fujimoto T

    Meeting Abstracts of the Physical Society of Japan   Vol. 49 ( 0 ) page: 70 - 70   1994

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    DOI: 10.11316/jpsgaiyog.49.4.0_70_2

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  95. 14a-DB-1 CD分子A^2Δ, B^2Σ^+状態における前期解離

    Danielsson M., Erman P., 菱川 明栄, Larsson M., Rachlew-Kallne E., Sundstrom G.

    日本物理学会講演概要集. 秋の分科会   Vol. 1993 ( 0 ) page: 54 - 54   1993

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    DOI: 10.11316/jpsgaiyoj.1993.4.0_54_1

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  96. 1a-L-10 Study of atomic processes in discharge plasma by using LIFS

    Ishida H., Kitamura T., Hishikawa A., Fujimoto T.

    Meeting Abstracts of the Physical Society of Japan   Vol. 48 ( 0 ) page: 64 - 64   1993

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    DOI: 10.11316/jpsgaiyog.48.4.0_64_1

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  97. 24a-P-7 Influence radiation trapping on polarizations of the resouance lines of helium II

    Hishikawa A., Mizuno H., Iwai T., Okasaka R.

    Meeting Abstracts of the Physical Society of Japan   Vol. 1991 ( 0 ) page: 28 - 28   1991

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    DOI: 10.11316/jpsgaiyoa.1991.4.0_28_1

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▼display all

Presentations 5

  1. 円偏光強レーザー場におけるO2分子の分子座標系光電子3次元運動量分布

    池谷大夢, 藤瀬光香, 松田晃孝, 伏谷瑞穂, 菱川明栄

    第101回日本化学会年会  2021.3.20  日本化学会

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    Event date: 2021.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン  

  2. Tunneling ionization of molecular hydrogen by using a high-repetition-rate pulse laser International conference

    S. Inaba, D. Ikeya, H. Fujise, A. Hishikawa

    The 4th IRCCS International Symposium “Multidimensional control over material structure and function”  2021.3.15 

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    Event date: 2021.3

    Language:English   Presentation type:Poster presentation  

  3. Association reaction of gaseous C6H14 in femtosecond laser filament studied by product mass spectrometry International conference

    Y. Okumura, A. Matsuda, A. Hishikawa

    The 4th IRCCS International Symposium “Multidimensional control over material structure and function”  2021.3.15 

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    Event date: 2021.3

    Language:English   Presentation type:Poster presentation  

  4. Development of a molecular dynamics measurement method in strong laser fields using a pulsed ion source

    M. Yamada, H. Hasegawa, A. Matsuda, M. Fushitani and A. Hishikawa

    The 4th IRCCS International Symposium “Multidimensional control over material structure and function”  2021.3.15 

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    Event date: 2021.3

    Language:English   Presentation type:Poster presentation  

  5. ω-2ω 強レーザー場中 CH4解離過程における非対称性と解離経路依存性

    長谷川景郁, 松田晃孝, 菱川明栄

    分子科学会オンライン討論会  2020.9.15  分子科学会

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    Event date: 2020.9

    Language:Japanese   Presentation type:Oral presentation (general)  

KAKENHI (Grants-in-Aid for Scientific Research) 15

  1. 強レーザー場円2色性によるキラリティ検出法の開拓

    Grant number:21K18929  2021.7 - 2024.3

    日本学術振興会  科学研究費助成事業  挑戦的研究(萌芽)

    菱川 明栄

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    Authorship:Principal investigator 

    Grant amount:\6370000 ( Direct Cost: \4900000 、 Indirect Cost:\1470000 )

  2. Multi-photon multiple ionization mechanism in short-wavelength intense laser field

    Grant number:21K03430  2021.4 - 2024.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Coinvestigator(s) 

  3. レーザートンネル電子運動量計測に基づく電子ダイナミクス可視化法の開拓

    Grant number:19H00887  2019.4 - 2022.3

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    菱川 明栄, 森下 亨

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    Authorship:Principal investigator 

    Grant amount:\55640000 ( Direct Cost: \42800000 、 Indirect Cost:\12840000 )

    化学反応や分子機能を司る電子のダイナミクスを複雑な解析を経ることなく可視化することを目的として,強レーザー場における「トンネルイオン化」を利用した新規手法の開拓を行う。特にトンネル電子の運動量分布に着目し,これを分子座標系で3次元計測することで,実時間で電子ダイナミクスを直接観測する新しい反応イメージング法の基盤を確立する。

  4. Development of electron dynamics imaging technique based on understanding of laser tunneling ionization process

    Grant number:16H04029  2016.4 - 2019.3

    HISHIKAWA Akiyoshi

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    Grant amount:\17940000 ( Direct Cost: \13800000 、 Indirect Cost:\4140000 )

    We studied laser tunneling ionization of molecules in ultrashort intense laser fields to develop an electron dynamics imaging technique. Two observables of tunneling ionization, (1) ionization rates and (2) electron transversal momentum distributions (TMDs), were measured to compare with predictions by tunneling ionization theories. It was demonstrated that one can (1) read out the asymmetric 2π highest occupied molecular orbital (HOMO) of nitric oxide by using shaped intense laser pulses and (2) obtain the TMDs of deuterium molecule from the cross sections of a photoelectron torus in the molecular frame.

  5. Real-time probing atomic core-hole decay

    Grant number:15K05228  2015.4 - 2018.3

    Hikosaka Yasumasa

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid) 

    In this research, we aimed to observe the electron emission process of atoms by using free electron laser SACLA of RIKEN, combined use of free electron laser (FEL) and near infrared (NIR) femtosecond laser. Using X-ray beamline BL 3 at SACLA, side-band formation by NIR laser was observed in the Auger electron spectra of rare gases. The sideband intensity enables us to optimize the spatial and temporal overlap by of the two lasers. In addition, a highly-excited states of single-charged xenon was probed by using NIR laser in combination with soft X-ray beamline BL1, and their decay was probed in real time.

  6. Study on fine-particle formation in laser filaments

    Grant number:26620004  2014.4 - 2017.3

    HISHIKAWA Akiyoshi

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    Grant amount:\3900000 ( Direct Cost: \3000000 、 Indirect Cost:\900000 )

    Many-body chemical reaction processes induced by intense laser fields are studied by using laser filament formed by femtosecond laser pulses focused by a long focusing length lens. Intense laser pulse (~40 fs, ~1mJ/pulse) were focussed to a gas-cell containing ethylene gas (~1 atm) to form a laser filament. The produced materials were analyzed by using TEM, EELS and XPS etc to show that the main products are hydrogenated amorphous carbons. It was found that the sp2/sp3 carbon ratio and the size of the nano-particles varies sensitively depending on the wavelength and intensity of the laser fields.

  7. Investigation of the multielectron dynamics of chemical reactions based on time-dependent molecular orbital picture: Its development and experimental verification

    Grant number:24245001  2012.4 - 2016.3

    Kono Hirohiko

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    We investigated the multielectron dynamics of molecules such as CO and N2 in intense laser fields by using electronic and nuclear wavepacket propagation methods and proposed laser control schemes of the generation of higher order harmonics which is a source of attosecond pulses. We experimentally demonstrated that the two C-O bonds of CO2 can be asymmetrically cleaved by changing the phase between two-color pulses, which provides a new possibility of the laser control of chemical reactions. We also established a method to simulate XFEL-induced Coulomb explosion of molecules for time-resolved molecular imaging.The results of application to iodouracil etc. are in good agreement with the experimental results.

  8. In-situ observation of molecules in intense laser fields by ultrafast photoelectron spectroscopy

    Grant number:24350006  2012.4 - 2015.3

    HISHIKAWA Akiyoshi

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    Authorship:Principal investigator 

    Grant amount:\18330000 ( Direct Cost: \14100000 、 Indirect Cost:\4230000 )

    A system for ultrafast photoelectron spectroscopy was constructed using laser high-order harmonics in extreme ultraviolet, which was successfully applied to femtosecond pump-probe real-time tracking of ultrafast electron wavepacket dynamics. The effect of electronic excitation in molecular dynamics in intense laser fields was studied by momentum imaging of dissociative ionization of UV-excited molecules. Based on the finding, a novel method to visualize electron dynamics in molecules in real time was proposed. Photoelectron spectroscopy of molecules before and after the irradiation of an intense laser pulse was performed, revealing selective excitation of specific electronic states in the laser field.

  9. Multi-ionization of atoms and molecules in intense short-wavelength laser fields

    Grant number:24540425  2012.4 - 2015.3

    HIKOSAKA Yasumasa

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid) 

    Multi-photon absorption processes of atoms in intense short-wavelength laser fields has been studied by photoelectron spectroscopy. We have applied the magnetic bottle electron spectroscopic method, to achieve effective photoelectron spectroscopic researches with light sources of ultra intense and high photon energy. We have studied the three-photon double ionization of Ar in intense extreme ultraviolet free-electron laser fields over a photon energy range of 19.6-22.0 eV. It is found that the double ionization to Ar2+ proceeds sequentially via the formation of singly charged Ar+ states and is enhanced around photon energies of 20.5 and 21.5 eV. Two types of resonances are identified in the two-photon ionization of the Ar+ states: (i) resonances to intermediate states at the one-photon energy level and (ii) those to autoionizing states above the Ar2+ ionization threshold.

  10. 分子ドレスト状態における核波束実時間追跡:コイシデンス画像法によるアプローチ

    Grant number:16032215  2004 - 2005

    菱川 明栄

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    Authorship:Principal investigator 

    Grant amount:\7600000 ( Direct Cost: \7600000 )

    強光子場における分子ダイナミクスのレーザー偏光方向に対する分子配向依存性を明らかにするために,12fs程度のパルス幅を持つ極短パルス強光子場中(〜10^<14>W/cm^2)におけるH_2Sのクーロン爆発過程をコインシデンス運動量画像法を用いて調べた。フェムト秒チタンサファイアレーザーシステムから出力された光パルス(波長800nm,パルス幅<40fs,繰り返し1kHz)の一部を,Arガス(〜0.1MPa)を充填したセル内に設置された中空ファイバーに導入しスペクトルの広帯域化を行った後、チャープミラーにより分散補償を行いパルス圧縮した。フリンジ分解自己相関波形から求められたパルス幅は9.0fsであり,パルスあたりのエネルギーとして0.4mJを得た。分子平面の方向はその法線ベクトル(n)を3体クーロン爆発過程によって観測されたH^+の運動量外積として定義し,クーロン爆発事象毎に決定した。光子場強度3×10^<11>W/cm^2における3体クーロン爆発過程,H_2S^<3+>→H^++S^++H^+,によって生成したH^+の運動量相関図には,p_1(=p_2)=37×10^3amu m/s及び45×10^3amu m/sに2つのピークが観測された。これら2つの成分はレーザー偏光ベクトル(ε)と分子平面が平行な場合(ε⊥n)および垂直な場合(ε//n)にそれぞれ観測され,異なる分子配向による分子ダイナミクスの違いを反映している事が明らかになった。測定された運動量からクーロン爆発直前のH-S結合距離R(H-S)は,ε⊥nの場合R(H-S)=2.6Å,ε//nの場合R(H-S)=1.9Åと見積もられた。このことは,分子平面が偏光ベクトルに対して平行な場合にH_2Sがより伸張した構造を持つことを示している。

  11. 電子-イオンコインシデンス運動量画像法による強光子場中分子ダイナミクス

    Grant number:15685001  2003 - 2004

    菱川 明栄

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    Authorship:Principal investigator 

    Grant amount:\26780000 ( Direct Cost: \20600000 、 Indirect Cost:\6180000 )

    本研究では,クーロン爆発によって生成した多価原子イオンと電離電子の運動量分布を同時計測し,イオンおよび電子の持つ運動量ベクトルの相関にもとづいて強光子場中分子ダイナミクスを明らかにすることを目的とする.本年度はこの目的のために開発したコインシデンス運動量画像測定システムを用いて,強光子場中分子から生成したイオンおよび電子の運動量画像計測を行った。光子場強度(0.15PW/cm^2,70fs)におけるアセトニトリルの2体クーロン爆発過程には,3つの異なる経路CH_3CN^<2+>→CH_<3-n>^++H_nCN^+(n=0,1,2),すなわちC-C結合が直接解離する経路(n=0)に加えてメチル基(-CH_3)からニトリル基(-CN)への水素移動を伴う経路(n=1,2)が存在することが明らかとなった。これらの経路に対する分岐比がほぼ等しいことから,水素移動反応がクーロン爆発と競合して極めて高速に進行することがわかった。また,レーザー偏光方向に対する生成フラグメントイオンの空間異方性の解析から,メチル基からニトリル基への水素移動が進むにつれて,親イオンCH_3CN^<2+>の寿命が長くなることを見いだした。
    さらに,コインシデンス画像法とポンプ-プローブ計測を組み合わせて強光子場において生成したCS_2^<2+>のダイナミクスを実時間追跡した。運動量相関図には,ポンプ-プローブ遅延時間に対して鋭敏に変化する2つの異なる成分が見いだされた。これらはそれぞれCS_2^<2+>のポテンシャル曲面上で反対称伸縮振動および対称伸縮振動方向へ移動する核波束に対応し,その収量から対称伸縮振動方向の運動に伴って2つのC-S結合が同時に解裂する過程が,強光子場において極めて効率よくおこることが示された。
    また,強光子場中CS_2から生成した光電子の画像観測を行い,基本波と2次高調波を混合した光子場において,光電子空間分布が位相に応じて鋭敏に変化することを見いだした。

  12. 強光子場中の分子・クラスターの構造と反応制御

    Grant number:14077205  2002 - 2005

    山内 薫

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    1.強光子場中炭化水素分子の超高速水素ダイナミクス
    強光子場中(〜10^<14>W/cm^2)において、メタノール分子からの水素分子イオン(H_2^+,H_3^+)生成を質量選別運動量画像法により明らかとした。フラグメントイオンの収量比と運動量ベクトル分布の異方性から、水素分子イオンの生成速度を明らかとした。また、コインシデンス運動量画像法を用いて強光子場中メタノール分子の2体クーロン爆発過程を調べ、フラグメントの角度分布の異方性から、前駆体CH_3OH^<2+>の寿命が、H^+放出の場合が70-290fs、H_2^+放出の場合が110-550fs、H_3^+放出の場合が1.4psよりも長いことが明らかとなった。さらに、H/D移動もしくはH/D交換を伴うC-O結合解離過程が確認され、フラグメントイオンの異方性および収量比より、水素移動が強レーザーのパルス時間幅の間に起こることが明らかとなった。
    2.軟X線強光子場におけるH_2,D_2の解離性越閾イオン化
    軟X線強光子場(〜3×10^<12>W/cm^2)におけるH_2およびD_2分子の解離性イオン化過程を調べた。高調波強度に対して、H_2より生成したH^+の生成量が1.7(1)次、D_2より生成したD^+の生成量が1.6(2)次の非線形依存性を示すことが明らかとなった。H^+とD^+の運動エネルギー分布およびその生成量の非線形性が、2つの協奏するイオン化過程、(i)1光子解離性イオン化と(ii)解離性2pπ_u状態への2光子吸収1価イオン化(ATI)によって解釈できることを示した。
    3.強光子場によるエタノールの選択的化学結合切断
    オープンループとクローズループを用いた最適化によって、強光子場中のエタノールイオンにおけるC-O結合解離のC-C結合解離に対する比率の最大化を行った。C-O結合解離の割合は強光子場の幅が約1psに到達すれば最大となることが明らかとなった。

  13. Light-dressed states of polyatomic molecules in intense laser fields studied by coincidence momentum measurements

    Grant number:13440122  2001 - 2002

    HISHIKAWA Akiyoshi

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    Authorship:Principal investigator 

    Grant amount:\11900000 ( Direct Cost: \11900000 )

    The three-body Coulomb explosion process of CS_2 in intense laser fields (〜 60 fs, 0.36x10^<15> W/cm^2), CS_2^<3+> → S^+ + C+ + S^+, is studied by the triple coincidence momentum imaging of the atomic fragment ions. The set of the observed momentum vectors of the fragment ions determined for respective explosion events exhibits a dear trajectory originating from the rotational motion of an intermediate CS^<2+> ion, formed in a sequential explosion process of CS_2^<3+> prior to the complete three-body fragmentation. The analysis based on the classical free-rotor model shows that the metastable CS2+ ion has a sufficiently longer lifetime than its rotational period (〜20ps). The molecular structure of CS_2^<3+> just before the Coulomb explosion is reconstructed from the average momentum values of the S^+ and C^+ ions produced through the concerted three-body Coulomb explosion pathways under the assumption that the potential between the fragments is Coulombic. The mean C-S bond length of <r> =2.5A and the azimuthally averaged S-C-S bond angle, <γ> = 145° thus determined indicate that structural deformation occurs to a large extent in the intense laser fields.

  14. High-resolution Doppler spectroscopy of light-dressed states of multi-electron molecules

    Grant number:11640386  1999 - 2000

    HISHIKAWA Akiyoshi

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    Authorship:Principal investigator 

    Grant amount:\3600000 ( Direct Cost: \3600000 )

    In order to clarify the role of light-dressed states in the dynamics of a multielectron molecule in intense laser fields, the dissociation processes, O_2^+→O^++O, in intense laser fields (100fs, 〜3×10^<14> W/cm^2) are studied at the laser wavelength of 795 nm and 398 nm on the basis of the momentum imaging maps of the O^+ fragment ions. The covariance map measurements are performed with high momentum resolution to assign securely the dissociation pathways. From the anisotropic momentum distribution of O^+ with respect to the laser polarization direction, the electronic states of O_2^+ are found to be coupled exclusively through parallel transitions in the course of the dissociation process. The released kinetic-energy of O^+ for both 795 nm and 398 nm are interpreted consistently by a sequential coupling model of light-dressed potential curves of O_2^+ in the quartet Π- state manifold.
    The dispersed fluorescence spectra of NO and O_2 were measured in the spectral range between 300 nm and 700 nm using a spectrometer equipped with a intensified CCD camera. The observed spectra exhibits a number of spectral lines, most of which were assigned to the electronic transition of the higher charged fragment ions, such as N^+, N^<2+>, O^+ and O^<2+>. A high-resolution (〜2 cm^<-1> ) measurement was performed for the N III 3^2P°→3^2S transition at 409.24 nm. The observed spectra show a doublet pattern when the laser polarization is directed towards the spectrometer, which is interpreted as a result of a large released kinetic energy imposed on the N^<2+> fragment ion through the Coulomb explosion of NO.Based on the kinetic energy estimated from the split pattern of the spectra, it was found that the N^<2+> fragment was produced through the Coulomb explosion process, NO^<4+>→N^<2+>+O^<2+>.

  15. 原子クラスターにおけるカオス的イオン化機構の解明

    Grant number:08740446  1996

    奨励研究(A)

    菱川 明栄

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    Grant amount:\1000000 ( Direct Cost: \1000000 )

    超音速ジェット中に生成した、水銀・ネオン2原子クラスター(HgNe)をレーザー2色2光子共鳴法によってイオン化し、イオン化スペクトルの測定を行った。リフレクトロン型飛行時間質量分析器を用いることによって、生成したイオン種を高質量分解能で検出し、単一質量イオン種についてのイオン化スペクトルを得ることができた。測定されたスペクトルには、HgNeのイオン化限界付近(83880-84020cm^<-1>)で振動自動イオン化によるシャープな構造が見いだされた。低エネルギー分解能測定(δν=0.7cm^<-1>)によって観測された主なピークは、フランクコンドン的に明るい、イオンコアの振動量子数がv^+=2,3のイオン化限界に収斂するd-リュードベリ系列に帰属された。さらにレーザーキャビティ内エタロンを用いた高エネルギー分解能測定(δν=0.05cm^<-1>)によって、それぞれのピークは複雑な共鳴構造を持つことが見いだされた。例えば、v^+=2リュードベリ系列の一つのピークは、フランクコンドン的に暗く、より準位密度の高いv^+=1リュードベリ系列との結合によっていくつかの小ピークにわかれる。イオン化スペクトルにおけるこのような階層構造は、光励起によって生成したv^+=2イオンコアを持つリュードベリ状態が、電子とイオンコアの衝突によるエネルギーの授受によって、v^+=1のリュードベリ状態に遷移し、最終的にv^+=0のイオンを生成する過程の存在を示唆している。半古典的に考えた場合、電子とイオンコアのエネルギーの授受は。衝突の際のイオンコアの振動の位相に依存するので、イオン化過程がストカスティックなものとなることが予想されている。多チャンネル量子欠損理論を用いたより詳細なスペクトルの解析によって、量子系におけるカオスのふるまいを探ることができると考えられる。

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Teaching Experience (On-campus) 7

  1. 物理化学基礎

    2020

  2. 光物理化学講究1

    2020

  3. 光物理化学講究3

    2020

  4. 無機物化分析

    2020

  5. Advanced Physical Chemistry

    2020

  6. Quantum Chemistry II

    2011

  7. 化学基礎 I

    2011

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