研究者詳細 - 伏谷　瑞穂

論文 - 伏谷　瑞穂

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Wave-packet manipulation of He Rydberg states by a seeded free-electron laser 査読有り

Dumergue M., Carpeggiani P.A., Csizmadia T., Danailov M., Demidovich A., De Ninno G., Di Fraia M., Eng-Johnsson P., Ertel D., Fujise H., Fushitani M., Giannessi L., Gopalakrishna H.N., Hishikawa A., Ibrahim H., Kühn S., Légaré F., Luo Y., Maroju P.K., Mauritsson J., Moioli M., Olofsson A., Peschel J., Plekan O., Pratt S.T., Raimondi L., Ribič P.R., Saito S., Sansone G., Shah R., Simpson E.R., You D., Zangrando M., Callegari C., Ueda K., Prince K.C.

Physical Review Research 6 巻 ( 4 ) 頁： 043323 2024年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review Research

We report a two-dimensional pump-control-probe spectroscopic study of the dynamics of singly excited He Rydberg-state wave packets with a seeded extreme ultraviolet (XUV) free-electron laser (FEL) source. A pair of coherent XUV pulses, defined by their coarse time separation and relative phase, created and manipulated the wave packets. The He atoms were postionized by infrared (IR) pulses, and the ion yield was measured as a function of XUV phase and IR arrival time. We tagged and sorted the relative phase of the XUV pulse pair on a single-shot basis by fitting each FEL spectrum with a suitable function that accounts for nonidealities of the XUV pulse pairs, associated with the seeding process; more generally, the fit returns the time-dependent electric field of the FEL spectra. The experimental two-dimensional maps of ion yields, measured as a function of IR (probe) delay and of XUV (pump-control) phase, were compared with the solution of the first-order time-dependent Schrödinger equation for this field. Despite the fact that the experimental conditions imply strong excitation, beyond the approximations of first-order perturbation theory, the simulated map satisfactorily reproduces the experimental one for temporally well-separated pulses. We show that by selecting data at appropriate values of pump-control phase, we enhance or suppress the amplitude of chosen wave-packet components consisting of two or more Rydberg states. When the temporal overlap of the pulse pair cannot be neglected, the phase reconstruction is underdetermined, and we provide a simplified comparison between data and simulations.

DOI： 10.1103/physrevresearch.6.043323

その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.6.043323/fulltext

State-selective dissociative double ionization of CH3I and CH2I2 via I 4d core-hole states studied by multi-electron–ion coincidence spectroscopy 査読有り

Mizuho Fushitani, Yasumasa Hikosaka, Motomichi Tashiro, Akiyoshi Hishikawa

The Journal of Chemical Physics 160 巻 ( 17 ) 頁： 174307 2024年5月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Chemical Physics

The dissociative double ionization of CH3I and CH2I2 irradiated with extreme ultraviolet light at hv = 100 eV is investigated by multi-electron-ion coincidence spectroscopy using a magnetic bottle type electron spectrometer. The spin-orbit state-resolved Auger electron spectra for the I 4d core-hole states, (I 4d3/2)−1 and (I 4d5/2)−1, provide clear identifications of electronic states of CH3I2+ and CH2I22+. The dominant ion species produced after the double ionization correlate with the Auger electron energy, showing that different fragmentation pathways are open depending on the electronic states populated by the Auger decay. Theoretical calculations are performed to understand the fragmentation from the doubly charged states and the observed spin-orbit specificity in the Auger decay.

DOI： 10.1063/5.0204769

Wave packet dynamics and control in excited states of molecular nitrogen 査読有り国際共著国際誌

Fushitani M., Fujise H., Hishikawa A., You D., Saito S., Luo Y., Ueda K., Ibrahim H., Légaré F., Pratt S.T., Eng-Johnsson P., Mauritsson J., Olofsson A., Peschel J., Simpson E.R., Carpeggiani P.A., Ertel D., Maroju P.K., Moioli M., Sansone G., Shah R., Csizmadia T., Dumergue M., Gopalakrishna H.N., Kühn S., Callegari C., Danailov M., Demidovich A., Raimondi L., Zangrando M., De Ninno G., Di Fraia M., Giannessi L., Plekan O., Ribic P.R., Prince K.C.

Journal of Chemical Physics 160 巻 ( 10 ) 頁： 104203 2024年3月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Chemical Physics

Wave packet interferometry with vacuum ultraviolet light has been used to probe a complex region of the electronic spectrum of molecular nitrogen, N2. Wave packets of Rydberg and valence states were excited by using double pulses of vacuum ultraviolet (VUV), free-electron-laser (FEL) light. These wave packets were composed of contributions from multiple electronic states with a moderate principal quantum number (n ∼ 4-9) and a range of vibrational and rotational quantum numbers. The phase relationship of the two FEL pulses varied in time, but as demonstrated previously, a shot-by-shot analysis allows the spectra to be sorted according to the phase between the two pulses. The wave packets were probed by angle-resolved photoionization using an infrared pulse with a variable delay after the pair of excitation pulses. The photoelectron branching fractions and angular distributions display oscillations that depend on both the time delays and the relative phases of the VUV pulses. The combination of frequency, time delay, and phase selection provides significant control over the ionization process and ultimately improves the ability to analyze and assign complex molecular spectra.

DOI： 10.1063/5.0188182

Imaging Ultrafast Dissociation Dynamics: OCS & Roaming in Formaldehyde Open Access

Endo T., Neville S.P., Ziems K.M., Lassonde P., Qu C., Schmidt B.E., Fujise H., Fushitani M., Hishikawa A., Gräfe S., Houston P.L., Bowman J.M., Schuurman M.S., Légaré F., Ibrahim H.

Springer Proceedings in Physics 300 巻頁： 75 - 82 2024年

出版者・発行元：Springer Proceedings in Physics

Upon photoexcitation, molecules break apart, following different dissociation reactions. We can image these dissociation pathways using Coulomb explosion imaging (CEI) and sometimes we can control them using asymmetric laser fields. In the formaldehyde molecule, we can see fragments following the direct, conventional dissociation path, as well as fragments deviating from this minimum energy path. So-called roaming fragments or “roamers” explore the potential energy landscape in a statistical manner and could be directly captured in real-time, despite the signal’s statistical character. This is possible due to the single-molecule sensitivity of CEI and we could show that the onset of roaming occurs actually several orders of magnitude earlier than previously expected. In the polar molecule OCS we go one step further by controlling the fragmentation process using two-color asymmetric laser fields. In addition to expected direct ionization effects, we also see post-ionization contributions, which are usually not visible in heavy polar molecules. We thus show in two different examples that CEI provides the means to extract new, unexpected pathways, which would otherwise remain hidden underneath a strong background.

DOI： 10.1007/978-3-031-47938-0_8

Capturing transient core-to-core resonances in Kr in intense extreme-ultraviolet laser fields by electron-ion coincidence spectroscopy 査読有り

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

Physical Review A (Letter) 107 巻 ( 2 ) 頁： L021101 2023年2月

Imaging and Controlling ultrafast Dissociation Dynamics; from conventional to surprising paths

Endo T., Neville S.P., Lassonde P., Qu C., Schmidt B.E., Fushitani M., Hishikawa A., Houston P.L., Bowman J.M., Schuurman M.S., Légaré F., Ibrahim H.

Proceedings of SPIE - The International Society for Optical Engineering 12419 巻 2023年

出版者・発行元：Proceedings of SPIE - The International Society for Optical Engineering

Upon photo-excitation of a molecule it will break apart. We can see fragments following direct, conventional dissociation paths, as well as fragments deviating from this minimum energy path. The latter are called roaming fragments and explore the potential energy landscape in a statistical manner. Dissociating and roaming fragments are directly captured using Coulomb explosion imaging (CEI) and individual pathways are distinguished based on state-of-the-art theory analysis.

DOI： 10.1117/12.2649247

Electronic relaxation and dissociation dynamics in formaldehyde: Pump wavelength dependence 査読有り

Endo T., Neville S.P., Lassonde P., Qu C., Fujise H., Fushitani M., Hishikawa A., Houston P.L., Bowman J.M., Légaré F., Schuurman M.S., Ibrahim H.

Physical Chemistry Chemical Physics 24 巻 ( 3 ) 頁： 1779 - 1786 2022年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

The effect of the incident UV pump wavelength on the subsequent excited state dynamics, electronic relaxation, and ultimate dissociation of formaldehyde is studied using first principles simulation and Coulomb explosion imaging (CEI) experiments. Transitions in a vibronic progression in the Ã ← X absorption band are systematically prepared using a tunable UV source which generates pulses centered at 304, 314, 329, and 337 nm. We find, both via ab initio simulation and experimental results, that the rate of excited state decay and subsequent dissociation displays a prominent dependence on which vibronic transition in the absorption band is prepared by the pump. Our simulations predict that nonadiabatic transition rates and dissociation yields will increase by a factor of >100 as the pump wavelength is decreased from 337 to 304 nm. The experimental results and theoretical simulations are in broad agreement and both indicate that the dissociation rate plateaus rapidly after ≈2 ps following an ultrafast sub-ps rise. This journal is

DOI： 10.1039/d1cp04264e

Roaming in Formaldehyde – and how to get there

Endo T., Neville S.P., Lassonde P., Qu C., Fujise H., Fushitani M., Hishikawa A., Houston P.L., Bowman J.M., Légaré F., Schuurman M.S., Ibrahim H.

Optics InfoBase Conference Papers 2022年

Electron-ion Coincidence Imaging of O<inf>2</inf> in Intense Laser Fields with Additional Dissociation Pulses

Ikeya D., Matsuda A., Fushitani M., Hishikawa A.

Optics InfoBase Conference Papers 2022年

Time-resolved photoelectron imaging of complex resonances in molecular nitrogen 査読有り

Fushitani M., Pratt S.T., You D., Saito S., Luo Y., Ueda K., Fujise H., Hishikawa A., Ibrahim H., Légaré F., Johnsson P., Peschel J., Simpson E.R., Olofsson A., Mauritsson J., Carpeggiani P.A., Maroju P.K., Moioli M., Ertel D., Shah R., Sansone G., Csizmadia T., Dumergue M., Harshitha N.G., Kühn S., Callegari C., Plekan O., Di Fraia M., Danailov M.B., Demidovich A., Giannessi L., Raimondi L., Zangrando M., De Ninno G., Ribič P.R., Prince K.C.

Journal of Chemical Physics 154 巻 ( 14 ) 頁： 144305 2021年4月

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Chemical Physics

We have used the FERMI free-electron laser to perform time-resolved photoelectron imaging experiments on a complex group of resonances near 15.38 eV in the absorption spectrum of molecular nitrogen, N2, under jet-cooled conditions. The new data complement and extend the earlier work of Fushitani et al. [Opt. Express 27, 19702-19711 (2019)], who recorded time-resolved photoelectron spectra for this same group of resonances. Time-dependent oscillations are observed in both the photoelectron yields and the photoelectron angular distributions, providing insight into the interactions among the resonant intermediate states. In addition, for most states, we observe an exponential decay of the photoelectron yield that depends on the ionic final state. This observation can be rationalized by the different lifetimes for the intermediate states contributing to a particular ionization channel. Although there are nine resonances within the group, we show that by detecting individual photoelectron final states and their angular dependence, we can identify and differentiate quantum pathways within this complex system.

DOI： 10.1063/5.0046577

Capturing roaming molecular fragments in real time 査読有り国際誌

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

SCIENCE 370 巻 ( 6520 ) 頁： 1072 - + 2020年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Science

Since the discovery of roaming as an alternative molecular dissociation pathway in formaldehyde (H2CO), 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 timeresolved 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.

DOI： 10.1126/science.abc2960

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

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

PHYSICAL REVIEW LETTERS 124 巻 ( 19 ) 2020年5月

記述言語：日本語出版者・発行元：Physical Review Letters

Ultrafast multiphoton ionization of Xe in strong extreme ultraviolet free-electron laser (FEL) fields (91 eV, 30 fs, 1.6×1012 W/cm2) has been investigated by multielectron-ion coincidence spectroscopy. The electron spectra recorded in coincidence with Xe4+ show characteristic features associated with two-photon absorption to the 4d-2 double core-hole (DCH) states and subsequent Auger decay. It is found that the pathway via the DCH states, which has eluded clear identification in previous studies, makes a large contribution to the multiple ionization, despite the long FEL pulse duration compared with the lifetime of the 4d core-hole states.

DOI： 10.1103/PhysRevLett.124.193201

Multielectron-Ion Coincidence Spectroscopy of Xe in Extreme Ultraviolet Laser Fields: Nonlinear Multiple Ionization via Double Core-Hole States 査読有り

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

Phys. Rev. Lett. 124 巻 ( 19 ) 頁： 193201 2020年5月

Femtosecond two-photon Rabi oscillations in excited He driven by ultrashort intense laser fields 査読有り

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

NATURE PHOTONICS 10 巻 ( 2 ) 頁： 102 - + 2016年2月

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Photonics

Coherent light-matter interaction provides powerful methods for manipulating quantum systems. 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. 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. 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. 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.

DOI： 10.1038/NPHOTON.2015.228

Determination of absolute cross-sections of nonresonant EUV-UV two-color two-photon ionization of he

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

Optics InfoBase Conference Papers 2014年

記述言語：日本語出版者・発行元：Optics InfoBase Conference Papers

Single-shot photoelectron spectroscopy was performed for nonresonant EUV-UV twocolor two-photon ionization of He. From data analysis on the shot-by-shot basis, the absolute cross-section was determined to be σ(2)(597nm, 268nm) = 4.1(6)×10-52 cm4 s. © 2014 OSA.

DOI： 10.1364/up.2014.08.tue.p2.5

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

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年

Ultrafast photoelectron spectroscopy of electron-ion wave packets in Rydberg N<inf>2</inf>

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

Optics InfoBase Conference Papers 2014年

Ultrafast coulomb explosion of formaldehyde in 7 and 35 fs intense laser fields studied by triple ion-coincidence momentum imaging

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

Optics InfoBase Conference Papers 2014年

EUV and soft X-ray photoelectron spectroscopy of isolated atoms and molecules using single-order laser high-harmonics at 42 eV and 91 eV 査読有り

Fushitani Mizuho, Matsuda Akitaka, Hishikawa Akiyoshi

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 184 巻 ( 11-12 ) 頁： 561 - 568 2012年1月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Electron Spectroscopy and Related Phenomena

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 1Π u) → Br( 2P 3/2) + Br( 2P 3/2), are presented. © 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2011.10.002

Applications of pump-probe spectroscopy 査読有り

Mizuho Fushitani

Annual Reports on the Progress of Chemistry - Section C 104 巻頁： 272 - 297 2008年

掲載種別：研究論文（学術雑誌）

This review outlines advances that have been made in recent years (2005-2007) in the study of ultrafast dynamics occurring in physical, chemical and biological research fields by using pump-probe techniques. Special emphasis is placed on coherent phenomena in materials and experimental achievements of coherent control of wave packets dynamics. After a brief theoretical description of pump-probe methods, an overview of nuclear and electronic coherences appearing in pump-probe spectroscopy is presented. Some of the highlights include molecular alignments, wave packet interferometry, hydrogen migration, and attosecond electron dynamics. © 2008 The Royal Society of Chemistry.

DOI： 10.1039/b703983m

Ultrafast dynamics of halogens in rare gas solids

Guehr M., Bargheer M., Fushitani M., Kiljunen T., Schwentner N.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 9 巻 ( 7 ) 頁： 779 - 801 2007年

Cage motions induced by electronic and vibrational excitations: Cl-2 in Ar 査読有り

Fushitani M, Schwentner N, Schroder M, Kuhn O

JOURNAL OF CHEMICAL PHYSICS 124 巻 ( 2 ) 2006年1月

Pump-probe spectroscopy with phase-locked pulses in the condensed phase: decoherence and control of vibrational wavepackets 査読有り

Fushitani M, Bargheer M, Guhr M, Schwentner N

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 7 巻 ( 17 ) 頁： 3143 - 3149 2005年

Nuclear spin selection rule in the photochemical reaction of CH3 in solid parahydrogen 査読有り

Fushitani M, Momose T

JOURNAL OF CHEMICAL PHYSICS 116 巻 ( 24 ) 頁： 10739 - 10743 2002年6月

Distinguishing the XUV-induced Coulomb explosion dynamics of iodobenzene using covariance analysis 査読有り

Walmsley T., Allum F., Harries J.R., Kumagai Y., Lim S., McManus J., Nagaya K., Britton M., Brouard M., Bucksbaum P., Fushitani M., Gabalski I., Gejo T., Hockett P., Howard A.J., Iwayama H., Kukk E., Lam C.S., Minns R.S., Niozu A., Nishimuro S., Niskanen J., Owada S., Razmus W.O., Rolles D., Somper J., Ueda K., Unwin J., Wada S.I., Woodhouse J.L., Forbes R., Burt M., Warne E.M.

Journal of Physics B: Atomic, Molecular and Optical Physics 57 巻 ( 23 ) 頁： 235101 - 235101 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics B: Atomic, Molecular and Optical Physics

The primary and secondary fragmentation dynamics of iodobenzene following its ionization at 120 eV were determined using three-dimensional velocity map imaging and covariance analysis. Site-selective iodine 4d ionization was used to populate a range of excited polycationic parent states, which primarily broke apart at the carbon-iodine bond to produce I+ with phenyl or phenyl-like cations (CnH x + or CnH x 2 + , with n = 1 - 6 and x = 1 - 5). The molecular products were produced with varying degrees of internal excitation and dehydrogenation, leading to stable and unstable outcomes. This further allowed the secondary dynamics of C 6 H x 2 + intermediates to be distinguished using native-frame covariance analysis, which isolated these processes in their own centre-of-mass reference frames. The mass resolution of the imaging mass spectrometer used for these measurements enabled the primary and secondary reaction channels to be specified at the level of individual hydrogen atoms, demonstrating the ability of covariance analysis to comprehensively measure the competing fragmentation channels of aryl cations, including those involving intermediate steps.

DOI： 10.1088/1361-6455/ad8799

その他リンク： https://iopscience.iop.org/article/10.1088/1361-6455/ad8799/pdf

Time-Resolved Probing of the Iodobenzene C-Band Using XUV-Induced Electron Transfer Dynamics 査読有り国際共著国際誌

Unwin, J; Razmus, WO; Allum, F; Harries, JR; Kumagai, Y; Nagaya, K; Britton, M; Brouard, M; Bucksbaum, P; Fushitani, M; Gabalski, I; Gejo, T; Hockett, P; Howard, AJ; Iwayama, H; Kukk, E; Lam, CS; McManus, J; Minns, RS; Niozu, A; Nishimuro, S; Niskanen, J; Owada, S; Pickering, JD; Rolles, D; Somper, J; Ueda, K; Wada, SI; Walmsley, T; Woodhouse, JL; Forbes, R; Burt, M; Warne, EM

ACS PHYSICAL CHEMISTRY AU 2024年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Physical Chemistry Au

Time-resolved extreme ultraviolet spectroscopy was used to investigate photodissociation within the iodobenzene C-band. The carbon-iodine bond of iodobenzene was photolyzed at 200 nm, and the ensuing dynamics were probed at 10.3 nm (120 eV) over a 4 ps range. Two product channels were observed and subsequently isolated by using a global fitting method. Their onset times and energetics were assigned to distinct electron transfer dynamics initiated following site-selective ionization of the iodine photoproducts, enabling the electronic states of the phenyl fragments to be identified using a classical over-the-barrier model for electron transfer. In combination with previous theoretical work, this allowed the corresponding neutral photochemistry to be assigned to (1) dissociation via the 7B2, 8A2, and 8B1 states to give ground-state phenyl, Ph(X), and spin-orbit excited iodine and (2) dissociation through the 7A1 and 8B2 states to give excited-state phenyl, Ph(A), and ground-state iodine. The branching ratio was determined to be 87 ± 4% Ph(X) and 13 ± 4% Ph(A). Similarly, the corresponding amount of energy deposited into the internal phenyl modes in these channels was determined to be 44 ± 10 and 65 ± 21%, respectively, and upper bounds to the channel rise times were found to be 114 ± 6 and 310 ± 60 fs.

DOI： 10.1021/acsphyschemau.4c00036

Exploring the ultrafast and isomer-dependent photodissociation of iodothiophenes <i>via</i> site-selective ionization 査読有り国際共著国際誌

Razmus, WO; Allum, F; Harries, J; Kumagai, Y; Nagaya, K; Bhattacharyya, S; Britton, M; Brouard, M; Bucksbaum, PH; Cheung, K; Crane, SW; Fushitani, M; Gabalski, I; Gejo, T; Ghrist, A; Heathcote, D; Hikosaka, Y; Hishikawa, A; Hockett, P; Jones, E; Kukk, E; Iwayama, H; Lam, HVS; McManus, JW; Milesevic, D; Mikosch, J; Minemoto, S; Niozu, A; Orr-Ewing, AJ; Owada, S; Rolles, D; Rudenko, A; Townsend, D; Ueda, K; Unwin, J; Vallance, C; Venkatachalam, A; Wada, S; Walmsley, T; Warne, EM; Woodhouse, JL; Burt, M; Ashfold, MNR; Minns, RS; Forbes, R

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 26 巻 ( 16 ) 頁： 12725 - 12737 2024年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- and 3-iodothiophene is studied using ultrafast time-resolved extreme ultraviolet (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules and eventual I atom products are probed by site-selective ionization at the I 4d edge using intense XUV pulses, which induce multiple charges initially localized to the iodine atom. At C-I separations below the critical distance for charge transfer (CT), charge can redistribute around the molecule leading to Coulomb explosion and charged fragments with high kinetic energy. At greater C-I separations, beyond the critical distance, CT is no longer possible and the measured kinetic energies of the charged iodine atoms report on the neutral dissociation process. The time and momentum resolved measurements allow determination of the timescales and the respective product momentum and kinetic energy distributions for both isomers, which are interpreted in terms of rival ‘direct’ and ‘indirect’ dissociation pathways. The measurements are compared with a classical over the barrier model, which reveals that the onset of the indirect dissociation process is delayed by ∼1 ps relative to the direct process. The kinetics of the two processes show no discernible difference between the two parent isomers, but the branching between the direct and indirect dissociation channels and the respective product momentum distributions show isomer dependencies. The greater relative yield of indirect dissociation products from 262 nm photolysis of 3-iodothiophene (cf. 2-iodothiophene) is attributed to the different partial cross-sections for (ring-centred) π∗ ← π and (C-I bond localized) σ∗ ← (n/π) excitation in the respective parent isomers.

DOI： 10.1039/d3cp06079a

Orbital effects on tunnel-electron momentum distributions: Ar and H<inf>2</inf> studied by electron–ion coincidence momentum imaging 査読有り

Ikeya D., Fujise H., Inaba S., Takahashi M., Yamamoto M., Nakamura T., Nagao Y., Matsuda A., Fushitani M., Hishikawa A.

Journal of Electron Spectroscopy and Related Phenomena 262 巻頁： 147280 - 147280 2023年1月

掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Electron Spectroscopy and Related Phenomena

Three-dimensional momentum distributions of tunnel-electrons produced from Ar and H2 in circularly polarized intense laser fields (1035 nm, 35 fs, 2×1014 W/cm2) have been measured by electron–ion coincidence momentum imaging. The photoelectrons recorded with a gas mixture of Ar and H2 exhibit torus-like distributions in the momentum space. Although ionization potentials are similar (15.8 eV for Ar and 15.4 eV for H2), significant differences are identified in the radius and the width of the photoelectron torus recorded in coincidence with the counterpart ions (Ar+ and H2+). The differences are confirmed by theoretical calculations based on the strong-field approximation, showing that the orbital character of ionizing electrons is encoded in the momentum distribution of tunnel electrons.

DOI： 10.1016/j.elspec.2022.147280

Time-resolved shot-by-shot photoelectron spectroscopy of autoionizing states by EUV-free-electron-laser and near-IR laser pulses 査読有り

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

Physical Review A 104 巻 ( 2 ) 頁： 023102 2021年8月

担当区分：筆頭著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A

Ultrafast dynamics of highly excited Rydberg states of is investigated by time-resolved shot-by-shot photoelectron spectroscopy with EUV-free-electron-laser pump (40.8 eV) and near-infrared probe (1.56 eV) pulses. Sorting the single-shot spectra in the order of relative delay between the two pulses allows for investigating ultrafast decays of intermediate states participating in the double ionization of Xe. Observed photoelectron spectra show a biexponential decay within ∼100 fs and ∼300 ps in addition to constant signals lasting longer than 1 ns. These ultrafast decays reflect the lifetimes of autoionizing Rydberg states converging to electronically excited states of . The results demonstrate that time-resolved shot-by-shot EUV-free-electron-laser photoelectron spectroscopywith a synchronized optical laser provides a powerful tool for investigating ultrafast electron emission processes.

DOI： 10.1103/physreva.104.023102

その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevA.104.023102/fulltext

On the measurement of statistical dynamics using the method of Coulomb explosion imaging

Endo T., Neville S.P., Wanie V., Beaulieu S., Qu C., Lassonde P., Schmidt B.E., Fujise H., Fushitani M., Hishikawa A., Houston P.L., Bowman J.M., Schuurman M.S., Légaré F., Ibrahim H.

AIP Conference Proceedings 2343 巻 2021年3月

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

Using time-resolved Coulomb explosion imaging (CEI) in an ultraviolet (UV) pump near infrared (NIR) probe experiment, we directly image the different dissociation dynamics in the formaldehyde molecule. Different pathways are distinguished from each other, despite their statistical nature. To extract such dynamics, hidden in a statistical background, calls for an elimination of noise. In our approach, we take advantage of CEI being a quasi-background-free technique.

DOI： 10.1063/5.0047930

Capturing roaming fragments in real time: A molecular road movie

Endo T.

Optics InfoBase Conference Papers 2020年11月

Ultrafast Reaction Imaging and Control by Ultrashort Intense Laser Pulses 査読有り

Hishikawa Akiyoshi, Matsuda Akitaka, Fushitani Mizuho

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 93 巻 ( 11 ) 頁： 1293 - 1304 2020年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Bulletin of the Chemical Society of Japan

Molecules irradiated with intense laser pulses (field intensity ∼1015W/cm2) 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

Characterization of soft X-ray FEL pulse duration with two-color photoelectron spectroscopy 査読有り

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

JOURNAL OF SYNCHROTRON RADIATION 27 巻 ( 5 ) 頁： 1362 - 1365 2020年9月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Synchrotron Radiation

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 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

Angle dependence of dissociative tunneling ionization of NO in asymmetric two-color intense laser fields 査読有り

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

PHYSICAL REVIEW A 100 巻 ( 5 ) 頁： 053422 2019年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A

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

Probing Rydberg-Rydberg interactions in N-2 by ultrafast EUV-NIR photoelectron spectroscopy 査読有り

Fushitani Mizuho, Toida Yuto, Legare Francois, Hishikawa Akiyoshi

OPTICS EXPRESS 27 巻 ( 14 ) 頁： 19702 - 19711 2019年7月

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Optics Letters

The ultrafast dynamics of molecular nitrogen (N2) just below the ionization threshold has been investigated by time-resolved photoelectron spectroscopy using a single harmonic centered at hν = 15.38 eV. The evolution of the Rydberg wavepacket launched by the ultrashort EUV pulse is probed by a time-delayed femtosecond NIR laser pulse. The observed photoelectron spectra show two series of vibrational peaks to the ground X2Σg+ state and the first excited A2Πu state of N+2 . Among these, two photoelectron peaks with the vibrational quantum numbers vX+ = 4 and vA+ = 1 exhibit clear anti-phase oscillations with a period of 300 fs, showing that two Rydberg states converging to the X2Σg+ and A2Πu ionic states interact with each other, thus causing periodic switching in the population of the ion core states.

DOI： 10.1364/OE.27.019702

Coincidence momentum imaging of four- and three-body Coulomb explosion of formaldehyde in ultrashort intense laser fields 査読有り

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

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 228 巻頁： 25 - 30 2018年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Electron Spectroscopy and Related Phenomena

Ion-coincidence momentum imaging of Coulomb explosion of formaldehyde (H2CO) in femtosecond intense laser fields (800 nm, 1.3 × 1015 W/cm2) 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+ + CO+ and H+ + CH+ + 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

強レーザーパルスを用いた量子状態の超高速多光子操作招待有り査読有り

伏谷瑞穂，菱川明栄

レーザー研究 45 巻頁： 493-497 2017年8月

Selective bond breaking of CO2 in phase-locked two-color intense laser fields: laser field intensity dependence 査読有り

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

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 巻 ( 5 ) 頁： 3550 - 3556 2017年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

Selective bond breaking of CO2 in phase-locked ω-2ω two-color intense laser fields (λ = 800 nm and 400 nm, total field intensity I ∼ 1014 W cm-2) has been investigated by coincidence momentum imaging. The CO+ and O+ fragment ions produced by two-body Coulomb explosion, CO22+ → 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 × 1014 W cm-2, the largest fragment asymmetry is observed when the relative phase between the ω and 2ω laser fields is ∼0 and π. 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

Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics 査読有り

Fushitani Mizuho, Hishikawa Akiyoshi

STRUCTURAL DYNAMICS-US 3 巻 ( 6 ) 頁： 062602 2016年11月

担当区分：筆頭著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Structural Dynamics

We present applications of extreme ultraviolet (XUV) single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N2 molecules.

DOI： 10.1063/1.4964775

Imaging Electronic Excitation of NO by Ultrafast Laser Tunneling Ionization 査読有り

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

PHYSICAL REVIEW LETTERS 116 巻 ( 16 ) 2016年4月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review Letters

Tunneling-ionization imaging of photoexcitation of NO has been demonstrated by using few-cycle near-infrared intense laser pulses (8 fs, 800 nm, 1.1×1014 W/cm2). The ion image of N+ fragment ions produced by dissociative ionization of NO in the ground state, NO (X2Π,2π)→NO++e-→N++O+e-, exhibits a characteristic momentum distribution peaked at 45° with respect to the laser polarization direction. On the other hand, a broad distribution centered at ∼0° appears when the A2Σ+ (3sσ) 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

Photoelectron sidebands induced by a chirped laser field for shot-by-shot temporal characterization of FEL pulses 査読有り

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

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 49 巻 ( 3 ) 2016年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics B: Atomic, Molecular and Optical Physics

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 Schrödinger 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

Coincidence momentum imaging of asymmetric Coulomb explosion of CO2 in phase-locked two-color intense laser fields 査読有り

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

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 207 巻頁： 50 - 54 2016年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Electron Spectroscopy and Related Phenomena

Coulomb explosion of CO2, CO2 → CO22+ + 2e- → CO+ + O+ + 2e-, in phase-locked two-color ultrashort intense laser fields (800 nm and 400 nm, ∼1014 W/cm2) 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 (∼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+.

DOI： 10.1016/j.elspec.2015.12.010

22pAE-11 極紫外レーザー高次高調波によるN_2リュードベリ波束ダイナミクスの超高速光電子分光

伏谷瑞穂, 樋田裕斗, Legare Francois, 菱川明栄

日本物理学会講演概要集 71 巻頁： 819 - 819 2016年

Correlation between Photoeletron and Photoion in Ultrafast Multichannel Photoionization of Ar 査読有り

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

INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2015 (ICCMSE 2015) 1702 巻 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

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 2PJ (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 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

Ion-Coincidence Momentum Imaging of Three-Body Coulomb Explosion of Formaldehyde in Ultrashort Intense Laser Fields 査読有り

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

INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2015 (ICCMSE 2015) 1702 巻 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

Three-body Coulomb explosion of formaldehyde (H2CO) in intense 7- and 35-fs laser fields (1.3 × 1015 W/cm2) has been investigated by using ion-coincidence momentum imaging technique. Two types of explosion pathways from the triply charged state, H2CO3+ → (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

Fragment anisotropy on dissociative ionization of NO in two-color intense laser fields 査読有り

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

XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12 635 巻 ( 11 ) 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Journal of Physics: Conference Series

Dissociative ionization of NO, NO → NO+ + e- → N+ + O + e-, in ω-2ω two-color phase-controlled intense laser fields was investigated by three-dimensional ion momentum imaging. The momentum image of the N+ ion exhibited anisotropic distributions peaked at 35° against the laser polarization, which show clear left-right asymmetry depending on the ω-2ω 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

その他リンク： http://orcid.org/0000-0003-1444-8917

Determination of Absolute Cross-Sections of Nonresonant EUV-UV Two-Color Two-Photon Ionization of He 査読有り

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

ULTRAFAST PHENOMENA XIX 162 巻頁： 109 - 112 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Springer Proceedings in Physics

Single-shot photoelectron spectroscopy was performed for nonresonant EUV-UV two-color two-photon ionization of He. From data analysis on the shotby- shot basis, the absolute cross-section was determined to be σ(2) (59.7 nm, 268 nm) = 4.1(6) × 10-52 cm4 s.

DOI： 10.1007/978-3-319-13242-6_26

その他リンク： http://orcid.org/0000-0003-1444-8917

Ultrafast two-photon Rabi oscillations in excited He driven by femtosecond intense laser fields 査読有り

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

XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12 635 巻 ( 9 ) 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Journal of Physics: Conference Series

We demonstrate ultrafast multiphoton coherent excitation in near-infrared intense laser fields (≤10 TW/cm2) using excited helium in the 1s2p (1P) 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

その他リンク： http://orcid.org/0000-0003-1444-8917

Five-photon sequential double ionization of He in intense extreme-ultraviolet free-electron laser fields 査読有り

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 90 巻頁： 053403 2014年11月

Five-photon sequential double ionization of He in intense extreme-ultraviolet free-electron laser fields 査読有り

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

PHYSICAL REVIEW A 90 巻 ( 5 ) 2014年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A - Atomic, Molecular, and Optical Physics

A multiphoton ionization process of He in intense extreme ultraviolet free-electron laser fields is investigated in a photon energy range of hv=20.1-20.8eV 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+(2s2S) 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

Photoelectron-photoion correlation in ultrafast multichannel photoionization of Ar 査読有り

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

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 47 巻 ( 19 ) 頁： 195602 2014年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics B: Atomic, Molecular and Optical Physics

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

Dissociative ionization of NO in few-cycle intense laser fields : Effects of pi-sigma electronic transition 査読有り

Endo Tomoyuki, Fushitani Mizuho, Matsuda Akitaka, Hishikawa Akiyoshi

XXVIII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC) 488 巻 ( SECTION 3 ) 2014年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Journal of Physics: Conference Series

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 π-σ electronic transition is clearly reflected in the spatial anisotropy of the fragmention, N+.

DOI： 10.1088/1742-6596/488/3/032025

その他リンク： http://orcid.org/0000-0003-1444-8917

Two-photon rabi oscillations of excited he atoms in ultrafast strong laser field ionization 査読有り

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年

Nonresonant EUV-UV two-color two-photon ionization of He studied by single-shot photoelectron spectroscopy 査読有り

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

PHYSICAL REVIEW A 88 巻 ( 6 ) 頁： 063422 2013年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A - Atomic, Molecular, and Optical Physics

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 σ(2)=4.1(6)×10-52 cm4 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. © 2013 American Physical Society.

DOI： 10.1103/PhysRevA.88.063422

Resonances in three-photon double ionization of Ar in intense extreme-ultraviolet free-electron laser fields studied by shot-by-shot photoelectron spectroscopy 査読有り

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

PHYSICAL REVIEW A 88 巻 ( 2 ) 頁： 023421 2013年8月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A - Atomic, Molecular, and Optical Physics

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 Ar+ ionization threshold. © 2013 American Physical Society.

DOI： 10.1103/PhysRevA.88.023421

Time-resolved Four-body Coulomb Explosion Imaging of Correlated Dynamics of Hydrogen Atoms in Acetylene Dication 査読有り

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

XVIIITH INTERNATIONAL CONFERENCE ON ULTRAFAST PHENOMENA 41 巻 2013年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：EPJ Web of Conferences

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

Ultrafast Nonlinear Double Excitations of He in Intense EUV FEL Fields 査読有り

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

XVIIITH INTERNATIONAL CONFERENCE ON ULTRAFAST PHENOMENA 41 巻 2013年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：EPJ Web of Conferences

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

Phase Sensitive Control of Vibronic Guest-Host Interaction: Br-2 in Ar Matrix (vol 113, pg 7439, 2009) 査読有り

Heide Ibrahim, Monika Hejjas, Mizuho Fushitani, Nikolaus Schwentner

JOURNAL OF PHYSICAL CHEMISTRY A 116 巻 ( 10 ) 頁： 2598 - 2598 2012年3月

Erratum: Phase sensitive control of vibronic guest-host interaction: Br <inf>2</inf> in Ar matrix (Journal of Physical Chemistry A (2009) 113: 26 (7439-7450) DOI: 10.1021/jp900287m) 査読有り

Ibrahim, H., Héjjas, M., Fushitani, M., Schwentner, N.

Journal of Physical Chemistry A 116 巻 ( 10 ) 頁： 2598 - 2598 2012年

Visualizing correlated dynamics of hydrogen atoms in acetylene dication by time-resolved four-body coulomb explosion imaging 査読有り

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

Springer Proceedings in Physics 125 巻頁： 317 - 322 2012年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Springer Proceedings in Physics

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

Enhanced Nonlinear Double Excitation of He in Intense Extreme Ultraviolet Laser Fields 査読有り

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

PHYSICAL REVIEW LETTERS 107 巻 ( 24 ) 頁： 243003 2011年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review Letters

Nonlinear, three-photon double excitation of He in intense extreme ultraviolet free-electron laser fields (∼24.1eV, ∼5TW/cm,sup>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 Schrödinger 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. © 2011 American Physical Society.

DOI： 10.1103/PhysRevLett.107.243003

A magnetic-bottle multi-electron-ion coincidence spectrometer 査読有り

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

REVIEW OF SCIENTIFIC INSTRUMENTS 82 巻 ( 10 ) 頁： 103105 2011年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Review of Scientific Instruments

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 → CS 22+e-e-, in ultrashort intense laser fields (2.8 × 1013W/cm2, 280 fs, 1030 nm) to clarify the electron correlation below the rescattering threshold. © 2011 American Institute of Physics.

DOI： 10.1063/1.3648133

Time-resolved EUV photoelectron spectroscopy of dissociating I-2 by laser harmonics at 80 nm 査読有り

Fushitani Mizuho, Matsuda Akitaka, Hishikawa Akiyoshi

OPTICS EXPRESS 19 巻 ( 10 ) 頁： 9600 - 9606 2011年5月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Optics Express

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 I2 in the B 3Π(0u+) and B" 1Π(1u) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (∼400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states. © 2011 Optical Society of America.

DOI： 10.1364/OE.19.009600

Visualizing hydrogen atoms migrating in acetylene dication by time-resolved three-body and four-body Coulomb explosion imaging 査読有り

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

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 13 巻 ( 19 ) 頁： 8697 - 8704 2011年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

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 (∼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 2D24+ → D+ + C+ + C+ + D+. © 2011 the Owner Societies.

DOI： 10.1039/c0cp02333g

Infrared spectroscopy of rovibrational transitions of methyl radicals (CH3, CD3) in solid parahydrogen 査読有り

Hoshina Hiromichi, Fushitani Mizuho, Momose Takamasa

JOURNAL OF MOLECULAR SPECTROSCOPY 268 巻 ( 1-2 ) 頁： 164 - 172 2011年

Multiphoton Double Ionization of Ar in Intense Extreme Ultraviolet Laser Fields Studied by Shot-by-Shot Photoelectron Spectroscopy 査読有り

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

PHYSICAL REVIEW LETTERS 105 巻 ( 13 ) 2010年9月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review Letters

Photoelectron spectroscopy has been performed to study the multiphoton double ionization of Ar in an intense extreme ultraviolet laser field (hν∼21eV, ∼5TW/cm2), 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+hν→Ar++e- and Ar ++2hν→Ar2++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+. © 2010 The American Physical Society.

DOI： 10.1103/PhysRevLett.105.133001

Phase Sensitive Control of Vibronic Guest-Host Interaction: Br-2 in Ar Matrix 査読有り

Ibrahim Heide, Hejjas Monika, Fushitani Mizuho, Schwentner Nikolaus

JOURNAL OF PHYSICAL CHEMISTRY A 113 巻 ( 26 ) 頁： 7439 - 7450 2009年7月

Multiple Explosion Pathways of the Deuterated Benzene Trication in 9-fs Intense Laser Fields 査読有り

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

JOURNAL OF PHYSICAL CHEMISTRY A 113 巻 ( 11 ) 頁： 2254 - 2260 2009年3月

Electron-ion coincidence momentum imaging of molecular dissociative ionization in intense laser fields: Application to CS2 査読有り

Matsuda Akitaka, Fushitani Mizuho, Hishikawa Akiyoshi

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 169 巻 ( 2-3 ) 頁： 97 - 101 2009年2月

Time-resolved reaction imaging by intense few-cycle laser pulses and laser high-order harmonics 査読有り

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

Journal of Physics: Conference Series 185 巻 2009年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Institute of Physics Publishing

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

Femtosecond pump-probe 2D optical Kerr effect spectroscopy of molecular hydrogen crystals 査読有り

Koenigsmann Falk, Fushitani Mizuho, Owschimikow Nina, Anderson David T., Schwentner Nikolaus

CHEMICAL PHYSICS LETTERS 458 巻 ( 4-6 ) 頁： 303 - 307 2008年6月

Control of chromophore-to-bath coupling by interferometry: Cl-2 vibrational wave packets in solid Ar 査読有り

Fushitani M., Bargheer M., Guehr M., Ibrahim H., Schwentner N.

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 41 巻 ( 7 ) 2008年4月

Nuclear spin conversion of methane in solid parahydrogen 査読有り

Miyamoto Yuki, Fushitani Mizuho, Ando Daisuke, Momose Takamasa

JOURNAL OF CHEMICAL PHYSICS 128 巻 ( 11 ) 2008年3月

Acetylene-vinylidene isomerization in ultrashort intense laser fields studied by triple ion-coincidence momentum imaging 査読有り

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

JOURNAL OF CHEMICAL PHYSICS 128 巻 ( 8 ) 2008年2月

Visualizing recurrently migrating hydrogen in acetylene dication by intense ultrashort laser pulses 査読有り

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

PHYSICAL REVIEW LETTERS 99 巻 ( 25 ) 2007年12月

In situ photolysis of CD3I in solid orthodeuterium 査読有り

Fushitani Mizuho, Miyamoto Yuki, Hoshina Hiromichi, Momose Takamasa

JOURNAL OF PHYSICAL CHEMISTRY A 111 巻 ( 49 ) 頁： 12629 - 12634 2007年12月

Coherent phonons in the zone boundary region of solid Ar doped with Cl2 査読有り

Mizuho Fushitani, Nikolaus Schwentner, Maike Schroeder, Oliver Kuehn

ULTRAFAST PHENOMENA XV 88 巻頁： 618 - + 2007年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：SPRINGER-VERLAG BERLIN

We report on coherent zone-boundary phonons of solid Ar doped with Cl-2 in pump-probe spectra. Comparison with molecular dynamic simulation shows that specific motions of Ar atoms in the (100) plane are responsible for the observed oscillations.

Visualizing recurrently migrating hydrogen by few-cycle intense laser pulses 査読有り

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

XXV INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS 88 巻 2007年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：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+) -> 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

Coherence and control of molecular dynamics in rare gas matrices

Bargheer Matias, Borowski Alexander, Cohen Arik, Fushitani Mizuho, Gerber R. Benny, Guehr Markus, Hamm Peter, Ibrahim Heide, Kiljunen Toni, Korolkov Mikhail V., Kuehn Oliver, Manz Joern, Schmidt Burkhard, Schroeder Maike, Schwentner Nikolaus

ANALYSIS AND CONTROL OF ULTRAFAST PHOTOINDUCED REACTIONS 87 巻頁： 257 - 385 2007年

Coherent phonons in the zone boundary region of solid Ar doped with Cl2

Fushitani Mizuho, Schwentner Nikolaus, Schroeder Maike, Kuehn Oliver

ULTRAFAST PHENOMENA XV 88 巻頁： 618 - + 2007年

Correlation between nuclear spin ratio of cyclic C3H2 and chemical evolution in TMC-1 cores

Morisawa Yusuke, Fushitani Mizuho, Kato Yoshiyasu, Hoshina Hiromichi, Simizu Zenzo, Watanabe Shiori, Miyamoto Yuki, Kasai Yasuko, Kawaguchi Kentarou, Momose Takamasa

ASTROPHYSICAL JOURNAL 642 巻 ( 2 ) 頁： 954 - 965 2006年5月

Correlation between nuclear spin ratio of cyclic C3H2 and chemical evolution in TMC-1 cores 査読有り

Yusuke Morisawa, Mizuho Fushitani, Yoshiyasu Kato, Hiromichi Hoshina, Zenzo Simizu, Shiori Watanabe, Yuki Miyamoto, Yasuko Kasai, Kentarou Kawaguchi, Takamasa Momose

ASTROPHYSICAL JOURNAL 642 巻 ( 2 ) 頁： 954 - 965 2006年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IOP PUBLISHING LTD

The ortho-to-para nuclear spin ratio of cyclopropenylidene ( cyclic C3H2) in TMC-1 cores was investigated using the 45 m radio telescope at Nobeyama Radio Observatory. We have observed four ortho lines (J(KaKc) = 2(12) - 1(01), 3(12) - 3(03), 3(21) - 3(12), and 3(30) - 3(21)) and four para lines (J(KaKc) 2(02) - 1(11), 2(11) - 2(02), 2(20) - 2(11), and 3(22) - 3(13)) of cyclic C3H2 in six cores in TMC-1. A statistical equilibrium analysis of the observed intensities revealed apparent correlation between the ortho-to-para ratio of cyclic C3H2 and chemical evolution of the molecular cloud; the ortho-to-para ratio in younger cores is less than 2, while that in older cores is close to the statistical ratio of 3. A simple chemical model calculation indicates that the correlation is ascribed to the conservation of nuclear spin angular momenta in chemical reactions relevant to the production, destruction, and reproduction of cyclic C3H2. Since cyclic C3H2 has been observed in a variety of sources, the ortho-to-para ratio of cyclic C3H2 may be a useful probe of chemical evolution of molecular clouds.

DOI： 10.1086/501041

Chemical reactions in quantum crystals 査読有り

Momose T, Fushitani M, Hoshina H

INTERNATIONAL REVIEWS IN PHYSICAL CHEMISTRY 24 巻 ( 3-4 ) 頁： 533 - 552 2005年12月

Search for CCH-, NCO-, and NCS- Negative Ions in Molecular Clouds 査読有り

Morisawa Y, Hoshina H, Kato Y, Simizu Z, Kuma S, Sogoshi N, Fushitani M, Watanabe S, Miyamoto Y, Momose T, Kasai Y, Kawaguchi K

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 57 巻 ( 2 ) 頁： 325 - 334 2005年4月

Wavepacket interferometry and wavepacket dynamics in condensed phase 査読有り

M Bargheer, M Fushitani, M Guhr, N Schwentner

ULTRAFAST PHENOMENA XIV 79 巻頁： 304 - 306 2005年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：SPRINGER-VERLAG BERLIN

The diatomic Cl-2 in solid Ar is examined to discuss the information obtained by wavepacket interferometry in condensed phase and to contrast it with femtosecond pump-probe and linear absorption spectra.

Wavepacket interferometry and wavepacket dynamics in condensed phase

Bargheer M, Fushitani M, Guhr M, Schwentner N

ULTRAFAST PHENOMENA XIV 79 巻頁： 304 - 306 2005年

Tunneling chemical reactions in solid parahydrogen: Direct measurement of the rate constants of R+H-2 -> RH+H (R=CD3,CD2H,CDH2,CH3) at 5 K 査読有り

Hoshina H, Fushitani M, Momose T, Shida T

JOURNAL OF CHEMICAL PHYSICS 120 巻 ( 8 ) 頁： 3706 - 3715 2004年2月

High-resolution spectroscopy and the analysis of ro-vibrational transitions of molecules in solid parahydrogen 査読有り

Momose T, Hoshina H, Fushitani M, Katsuki H

VIBRATIONAL SPECTROSCOPY 34 巻 ( 1 ) 頁： 95 - 108 2004年1月

Stimulated Stokes downconversion in liquid and solid parahydrogen 査読有り

McCall BJ, Huneycutt AJ, Saykally RJ, Lindsay CM, Oka T, Fushitani M, Miyamoto Y, Momose T

APPLIED PHYSICS LETTERS 82 巻 ( 9 ) 頁： 1350 - 1352 2003年3月

Generation of infrared radiation by stimulated Raman scattering in para-hydrogen crystal at 5 K 査読有り

Mizuho Fushitani, Susumu Kuma, Yuuki Miyamoto, Hiroyuki Katsuki, Tomonari Wakabayashi, Takamasa Momose, Andrey F. Vilesov

Optics Letters 28 巻 ( 1 ) 頁： 37 - 39 2003年1月

掲載種別：研究論文（学術雑誌）

We report the preliminary results of our experiments with stimulated Raman scattering in para-hydrogen crystal aimed at developing a continuously tunable laboratory laser source of mid-infrared radiation. With laser pulses at 532 nm, a conversion efficieney for the first Stokes beam of as much as 20% in the forward direction was observed through a single-pass, 5-cm-long crystal. Generation of mid-infrared pulses at 4.5 μm was achieved by use of the output of a near-infrared pulsed laser (1.6 μm, 3 ns), and an absorption spectrum of gaseous CD4 molecules was successfully recorded. These results suggest use of the solid para-hydrogen Raman shifter as a promising light source for mid-infrared spectroscopy. © 2003 Optical Society of America.

DOI： 10.1364/OL.28.000037

Generation of infrared radiation by stimulated Raman scattering in para-hydrogen crystal at 5 K

Fushitani M, Kuma S, Miyamoto Y, Katsuki H, Wakabayashi T, Momose T, Vilesov AF

OPTICS LETTERS 28 巻 ( 1 ) 頁： 37 - 39 2003年1月

A study on diffusion of H atoms in solid parahydrogen 査読有り

Fushitani M, Momose T

LOW TEMPERATURE PHYSICS 29 巻 ( 9-10 ) 頁： 740 - 743 2003年

Quantum property of solid hydrogen as revealed by high-resolution laser spectroscopy 査読有り

Katsuki H, Fushitani M, Momose T

LOW TEMPERATURE PHYSICS 29 巻 ( 9-10 ) 頁： 832 - 837 2003年

The P-2(1/2)<- P-2(3/2) transition of the iodine atom photoproduced from alkyl iodides in solid parahydrogen: detection of new absorptions

Fushitani M, Momose T, Shida T

CHEMICAL PHYSICS LETTERS 356 巻 ( 3-4 ) 頁： 375 - 382 2002年4月

The <sup>2</sup>P<inf>1/2</inf> ← <sup>2</sup>P<inf>3/2</inf> transition of the iodine atom photoproduced from alkyl iodides in solid parahydrogen: Detection of new absorptions 査読有り

Mizuho Fushitani, Takamasa Momose, Tadamasa Shida

Chemical Physics Letters 356 巻 ( 3-4 ) 頁： 375 - 382 2002年4月

掲載種別：研究論文（学術雑誌）

Alkyl iodides were photolyzed in solid parahydrogen at about 5 K. The first photolysis with 253.7 nm photons yielded two products by reactions, RI + hv (253.7 nm) → Rfree + ·Ifree and (R·-·I), the latter being a complex between the radical R· and the iodine atom ·I. Subsequent photolysis with 193 nm photons activated the radical moiety in both products to induce a reaction, R· + H2 + hv (193 nm) → RH + ·H, which gave the products RHfree and (RH-·I). The radical R· and the alkane RH were characterized by the mid-IR absorption while the iodine atoms in ·Ifree and (R·-·I) and (RH-·I) were identified by the near IR absorption of the magnetic dipole transition of the atom. © 2002 Published by Elsevier Science B.V.

DOI： 10.1016/S0009-2614(02)00354-8

UV-photolysis of HI center dot center dot center dot CO2 complexes in solid parahydrogen: Formation of CO and H2O

Fushitani M, Shida T, Momose T, Rasanen M

JOURNAL OF PHYSICAL CHEMISTRY A 104 巻 ( 16 ) 頁： 3635 - 3641 2000年4月

UV-photolysis of HI⋯CO<inf>2</inf> complexes in solid parahydrogen: Formation of CO and H<inf>2</inf>O 査読有り

Mizuho Fushitani, Tadamasa Shida, Takamasa Momose, Markku Räsänen

Journal of Physical Chemistry A 104 巻 ( 16 ) 頁： 3635 - 3641 2000年4月

掲載種別：研究論文（学術雑誌）

The photochemistry of (HI)m⋯(CO2)n (m, n = 1,2, ...) complexes trapped in solid parahydrogen was studied by Fourier transform infrared absorption spectroscopy. Photolysis of the HI in the HI⋯(CO2)n complexes results in the generation of carbon monoxide and water molecules along with iodine atoms. Analysis of the observed spectra leads to the conclusion that the energetic hydrogen atom produced by the photolysis of HI initiates the reaction with one of the CCh molecules in the complexes as H + CO2 → OH + CO, which is followed by the secondary reaction of OH radicals with the matrix hydrogen as OH + H2 → H2O + H. These four-atom reactions are of practical importance in combustion processes as well as of theoretical importance in fundamental chemical dynamics. The result of the present study shows the usefulness of the parahydrogen matrix for fundamental study of photochemistry with the use of weakly bound complexes. © 2000 American Chemical Society.

Photoinduced reactions of methyl radical in solid parahydrogen

Fushitani M, Sogoshi N, Wakabayashi T, Momose T, Shida T

JOURNAL OF CHEMICAL PHYSICS 109 巻 ( 15 ) 頁： 6346 - 6350 1998年10月

Photoinduced reactions of methyl radical in solid parahydrogen 査読有り

Mizuho Fushitani, Norihito Sogoshi, Tomonari Wakabayashi, Takamasa Momose, Tadamasa Shida

Journal of Chemical Physics 109 巻 ( 15 ) 頁： 6346 - 6350 1998年

掲載種別：研究論文（学術雑誌）

Photolysis of methyl iodide in solid parahydrogen (p-H2) at about 5 K is studied with ultraviolet light at 253.7 and 184.9 nm. It is found that the light at 253.7 nm produces only methyl radical, whereas the light at 184.9 nm yields both methyl radical and methane. The mechanism of the formation of the photoproducts is elucidated by analyzing the temporal behavior of the observed vibrational absorption. It is concluded that methyl radical in the ground state does not react with p-H2 molecules appreciably but that the radical in the electronic excited state of B̃(2A1′), accessible by reabsorption of 184.9 nm photons by the radical, decomposes to a singlet methylene CH2 ã(1A1) and a hydrogen atom (2S) and that the singlet methylene reacts with a p-H2 molecule to give methane. © 1998 American Institute of Physics.

DOI： 10.1063/1.477276

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