研究者詳細 - 伏谷　瑞穂

論文 - 伏谷　瑞穂

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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

Scopus

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

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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

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PubMed

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

Scopus

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

Scopus

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

Scopus

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

Web of Science

Scopus

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

Web of Science

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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

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Scopus

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

Web of Science

Scopus

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

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Scopus

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

Web of Science

Scopus

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

Web of Science

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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

Web of Science

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