Updated on 2024/05/27

写真a

 
SOEJIMA Kouichi
 
Organization
Academic Assembly Institute of Science and Technology CHIKYU SEIBUTSU KAGAKU KEIRETU Professor
Faculty of Science Department of Science Professor
Title
Professor
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Degree

  • 博士(理学) ( 1993.3   東京都立大学 )

Research Interests

  • Electron Capture Process

  • Photo Ionization

  • Circular Dichroism

  • 電子捕獲反応

  • 多価イオン

  • 光電離

  • 円二色性

  • Multiply Charged Ions

  • Molecular reaction on very low temperature surfaces

Research Areas

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

  • Natural Science / Space and planetary sciences

Research History (researchmap)

  • Associate Professor, Faculty of Science,

    2001 - 2003

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  • 新潟大理学部 助教授

    2001 - 2003

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Research History

  • Niigata University   Faculty of Science Department of Science   Professor

    2017.4

  • Niigata University   Abolition organization Terrestrial Science   Professor

    2015.4 - 2017.3

  • Niigata University   Graduate School of Science and Technology Environmental Science and Technology   Associate Professor

    2010.4 - 2015.3

  • Niigata University   Graduate School of Science and Technology Environmental Science and Technology   Associate Professor

    2010.4 - 2015.3

  • Niigata University   Faculty of Science Department of Environmental Science   Associate Professor

    2004.4 - 2015.3

  • Niigata University   Graduate School of Science and Technology   Research Assistant

    1996.8 - 2001.12

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Education

  • Tokyo Metropolitan University   Graduate School of Science   物理学

    - 1993

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    Country: Japan

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  • Tokyo Metropolitan University   Graduate School, Division of Natural Science

    - 1993

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Professional Memberships

Committee Memberships

  • 日本物理学会   領域1世話人  

    2002   

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    Committee type:Academic society

    日本物理学会

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  • 原子衝突研究協会   企画委員  

    1997   

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    Committee type:Academic society

    原子衝突研究協会

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Papers

  • Specific chemical bond relaxation unraveled by analysis of shake-up satellites in the oxygen single site double core hole spectrum of CO2

    Anthony Ferté, Francis Penent, Jérôme Palaudoux, Hiroshi Iwayama, Eiji Shigemasa, Yasumasa Hikosaka, Kouichi Soejima, Pascal Lablanquie, Richard Taïeb, Stéphane Carniato

    Physical Chemistry Chemical Physics   2022

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1039/D1CP03947D

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  • Auger decay of the 3d hole in the isoelectronic series of Br, Kr+ , and Rb2+

    J. Keskinen, K. Jänkälä, S.-M. Huttula, T. Kaneyasu, Y. Hikosaka, E. Shigemasa, H. Iwayama, K. Soejima, K. Ito, L. Andric, M. A. Khalal, J. Palaudoux, F. Penent, P. Lablanquie

    Physical Review A   103 ( 3 )   2021.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society ({APS})  

    DOI: 10.1103/physreva.103.032828

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  • Single photon simultaneous K-shell ionization/excitation in C6H6: experiment and theory

    S Carniato, P Selles, A Ferté, N Berrah, A H Wuosmaa, M Nakano, Y Hikosaka, K Ito, M Žitnik, K Bučar, K Soejima, K Jänkälä, D Cubaynes, J-M Bizau, L Andric, M A Khalal, J Palaudoux, P Lablanquie, F Penent

    Journal of Physics B: Atomic, Molecular and Optical Physics   53 ( 24 )   244010 - 244010   2020.12

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    Publishing type:Research paper (scientific journal)   Publisher:{IOP} Publishing  

    DOI: 10.1088/1361-6455/abc663

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  • Advanced Computation Method for Double Core Hole Spectra: Insight into the Nature of Intense Shake-up Satellites

    Anthony Fert{\'{e } }, J{\'{e } }r{\^{o } }me Palaudoux, Francis Penent, Hiroshi Iwayama, Eiji Shigemasa, Yasumasa Hikosaka, Kouichi Soejima, Kenji Ito, Pascal Lablanquie, Richard Taïeb, St{\'{e } }phane Carniato

    The Journal of Physical Chemistry Letters   11 ( 11 )   4359 - 4366   2020.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society ({ACS})  

    DOI: 10.1021/acs.jpclett.0c01167

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  • Development of pulse selectors for the synchrotron radiation pulses from the Photon Factory 2.5 GeV ring to study multiple photoionization

    J Adachi, H Tanaka, T Kosuge, H Ishii, I H Suzuki, T Kaneyasu, T Taniguchi, T Odagiri, S Ohtaki, Y Tsuji, K Soejima, P Lablanquie, Y Hikosaka

    Journal of Physics: Conference Series   1412   152092 - 152092   2020.1

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    DOI: 10.1088/1742-6596/1412/15/152092

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  • Detection of Neutral Species in the MALDI Plume Using Femtosecond Laser Ionization: Quantitative Analysis of MALDI-MS Signals Based on a Semiequilibrium Proton Transfer Model Reviewed

    Tatsuro Shirota, Masashi Tsuge, Yasumasa Hikosaka, Kouichi Soejima, Kennosuke Hoshina

    JOURNAL OF PHYSICAL CHEMISTRY A   121 ( 1 )   31 - 39   2017.1

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

    We investigated neutral species in the matrix-assisted laser desorption and ionization (MALDI) plume using femtosecond laser ionization spectrometry with simultaneous measurement of the standard MALDI spectrum of the identical MALDI event induced by pulsed UV laser irradiation. The ratio of neutral species in the plume [A](p)/[M](p) (A = phenylalanine (Phe) or alanine (Ala), M = 2,5-dihydroxybenzoic acid (DHB)) was confirmed to be the same as that of the sample mixture in the range of [A](0)/[M](0) = 4 x 10(-4)-1, indicating the validity of the widely adopted approximation [A](p)/[M](p) = [A](0)/[M](0) in the reaction quotient of the proton transfer reaction MH+ + A reversible arrow M + AH(+). An effective parameter representing the extent of thermal equilibrium in the thermal proton transfer model is introduced for the first time. Numerical simulation based on this semiequilibrium model successfully reproduced variations of MALDI signal intensities AH(+) and MH+ with two parameters: the fraction of ionized matrix a <= 10(-5) and an effective temperature T = 1200 and 1100 K for Phe/DHB and Ala/DHB systems, respectively. These values show good agreement with those determined previously by different experimental approaches. The extent of thermal equilibrium was determined to be 95% and 98% for Phe/DHB and Ala/DHB systems, respectively, suggesting that the proton transfer reactions almost proceed to their thermal equilibrium.

    DOI: 10.1021/acs.jpca.6b09591

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  • Electron emission relevant to inner-shell photoionization of condensed water studied by multi-electron coincidence spectroscopy Reviewed

    Y. Hikosaka, R. Mashiko, Y. Konosu, K. Soejima, E. Shigemasa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   213   17 - 21   2016.11

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

    Multi-electron coincidence spectroscopy using a magnetic-bottle electron spectrometer has been applied to the study of the Auger decay following Ols photoionization of condensed H2O molecules. Coincidence Auger spectra are obtained for three different photoelectron energy ranges. In addition, the energy distribution of the slow electrons ejected in the Auger decay of the Ols core hole is deduced from three-fold coincidences. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2016.10.006

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  • Double core hole spectroscopy with synchrotron radiation Reviewed

    F. Penent, M. Nakano, M. Tashiro, T. P. Grozdanov, M. Zitnik, K. Bucar, S. Carniato, P. Selles, L. Andric, P. Lablanquie, J. Palaudoux, E. Shigemasa, H. Iwayama, Y. Hikosaka, K. Soejima, I. H. Suzuki, N. Berrah, A. H. Wuosmaa, T. Kaneyasu, K. Ito

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   204   303 - 312   2015.10

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

    In the last five years, a strong experimental and theoretical activity has been dedicated to the study of inner-shell double photoionization. Almost simultaneously, between 2009 and 2011, different experiments were performed using two different light sources: well established third generation synchrotron light sources that exist for more than two decades and recently developed x-ray free electron lasers (X-FEL) that provide brightness of about 10 orders of magnitude higher. The high photon flux of X-FEL has made possible the successive absorption of many x-ray photons by inner-shell electrons in femtosecond timescale. The possibility to create multiple inner-shell vacancies with this new X-FEL light source has resuscitated "prophetic" 25 years old calculations by Cederbaum et al. [1,2] concerning double K-shell ionization that could be of great interest when conventional Electron Spectroscopy for Chemical Analysis (ESCA) finds some limitations. As a feedback, this has stimulated new theoretical developments. On the other hand, it was considered practically out of reach to observe such states with conventional third generation synchrotron light sources due to the very weak probability to eject two inner-shell electrons by a single photon when the dominant process, that could mask everything else, is single inner-shell ionization. However, due to the development of very efficient detection techniques, it was also possible to perform spectroscopy of double core-hole states with excellent accuracy using third generation synchrotron sources.
    In this paper we give an outlook on the basis of recently published results, of the complementarity of these light sources for double core-hole spectroscopy. Some new developments and results are also presented with a prospective of what could be done in the future with the technical breakthrough that will be necessary to improve our further understanding of chemical analysis. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2015.06.015

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  • Site-specific formation of metastable OCS2+ studied by Auger-electron-ion coincidence method Reviewed

    T. Kaneyasu, M. Ito, K. Soejima, Y. Hikosaka, E. Shigemasa

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   48 ( 12 )   2015.6

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    We have studied the site-specific formation of metastable OCS2+ in the C1s and the O1s Auger decays of OCS molecules by using an Auger-electron-ion coincidence technique. The coincidence measurement reveals the metastable character of the Auger final states with the (3 pi)-2 configuration. The formation of metastable OCS2+ is observed negligibly in the C1s Auger decay and only weakly in the O1s Auger decay, in contrast to the favorable metastable formation previously reported for S2p Auger decay. It is found that the origin of the site-specificity in the formation of metastable OCS2+ arises from the localization effect of the valence orbital involved in the Auger transition. The dissociative dication states related to individual fragmentation pathways are also derived from the coincidence measurement.

    DOI: 10.1088/0953-4075/48/12/125101

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  • 17aAA-7 Site-specific formation of metastable OCS^<2+> studied by Auger-electron-ion coincidence method

    Kaneyasu T., Ito M., Soejima K., Hikosaka Y., Shigemasa E.

    Meeting Abstracts of the Physical Society of Japan   70   491 - 491   2015

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    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.2.0_491

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  • Molecular single photon double K-shell ionization Reviewed

    F. Penent, M. Nakano, M. Tashiro, T. P. Grozdanov, M. Zitnik, S. Carniato, P. Selles, L. Andric, P. Lablanquie, J. Palaudoux, E. Shigemasa, H. Iwayama, Y. Hikosaka, K. Soejima, I. H. Suzuki, N. Kouchi, K. Ito

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   196   38 - 42   2014.10

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    We have studied single photon double K-shell ionization of small molecules (N-2, CO, C2H2n, (n = 1-3),...) and the Auger decay of the resulting double core hole (DCH) molecular ions thanks to multi-electron coincidence spectroscopy using a magnetic bottle time-of-flight spectrometer. The relative cross-sections for single-site (K-2) and two-site (K-1K-1) double K-shell ionization with respect to single K-shell (K-1) ionization have been measured that gives important information on the mechanisms of single photon double ionization. The spectroscopy of two-site (K-1K-1) DCH states in the C2H2n (n = 1-3) series shows important chemical shifts due to a strong dependence on the C-C bond length. In addition, the complete cascade Auger decay following single site (K-2) ionization has been obtained. (C) 2013 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2013.10.002

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  • Lifetime broadening of atomic lines produced upon ultrafast dissociation of HCl and HBr Reviewed

    P. Lablanquie, H. Iwayama, F. Penent, K. Soejima, E. Shigemasa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   195   96 - 100   2014.8

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    Ultrafast dissociation of the HCl and HBr molecules excited respectively to the 2p(3/2) -&gt; sigma* and 3d(5/2) -&gt; sigma* resonances are studied with high resolution photoelectron spectroscopy. Sharp vibrational molecular lines and broad atomic lines are observed. The analysis of the profile of the atomic lines gives access to the lifetimes of the inner shell 2p(3/2) hole in the Cl* (2p(3/2))(-1) 3s(2)3p(6) configuration, and the inner shell 3d(5/2) hole in the Br* (3d(5/2))(-1) 4s(2)4p(6) configuration. (C) 2014 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2014.06.006

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  • Site-specific formation of metastable dications following inner-shell ionization of CO2 Reviewed

    Y. Hikosaka, Y. Shibata, K. Soejima, H. Iwayama, E. Shigemasa

    CHEMICAL PHYSICS LETTERS   603   46 - 50   2014.5

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    An Auger-electron-ion coincidence method is applied to study the site-specific formation of metastable CO22+ in the C1s and O1s Auger decays of CO2. It is found that only dication states with the electronic configuration of 1 pi(-2)(g) are relevant to the metastable formation. These dication states are favorably produced in the O1s Auger decay, because of the charge distribution of the 1 pi(g) orbital localizing at the O site. Fragmentation channels of dissociative CO22+ states are also investigated. (C) 2014 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.cplett.2014.04.030

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  • Double K-shell ionization in C2H2n(n=l,3), CO and N2

    M Nakano, F Penent, M Tashiro, T P Grozdanov, M {\v{Z } }itnik, S Carniato, P Selles, L Andric, P Lablanquie, J Palaudoux, E Shigemasa, H Iwayama, Y Hikosaka, K Soejima, I H Suzuki, N Kouchi, K Ito

    Journal of Physics: Conference Series   488 ( 2 )   022013 - 022013   2014.4

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    DOI: 10.1088/1742-6596/488/2/022013

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  • A high-resolution magnetic bottle electron spectrometer and its application to a photoelectron-Auger electron coincidence measurement of the L2,3VV Auger decay in CS2 Reviewed

    Y. Hikosaka, M. Sawa, K. Soejima, E. Shigemasa

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   192   69 - 74   2014.1

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    The energy resolution and the detection efficiency of a magnetic bottle electron spectrometer equipped with an electrostatic retarder are examined, with a particular focus on its application to electron coincidence measurements. The electrostatic retardation properly improves the energy resolving power of the spectrometer. No significant decrease in detection efficiency is observed when retardation voltages are applied. Photoelectron-Auger electron coincidence measurement of the L2,3VV Auger decay in CS2 is performed by using the magnetic bottle spectrometer, which reveals Auger transition intensities varying for the different core holes. (C) 2014 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2014.01.017

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  • Double K-shell ionization in C2H2n(n=1,3), CO and N-2 Reviewed

    M. Nakano, F. Penent, M. Tashiro, T. P. Grozdanov, M. Zitnik, S. Carniato, P. Selles, L. Andric, P. Lablanquie, J. Palaudoux, E. Shigemasa, H. Iwayama, Y. Hikosaka, K. Soejima, I. H. Suzuki, N. Kouchi, K. Ito

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

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    We have observed single photon one-site (K-2) and two-sites (K-1K-1) double K-shell ionization in C2H2n (n-1-3) sequence and in isoelectronic C2H2. N-2 and CO molecules. The spectroscopy of K-1K-1 states is much more sensitive to the bond length than conventional ESCA spectroscopy based on single K-shell ionization. The mechanism of single photon two-sites is due to a knock-out process in which a primary photoionized 1s electrons eject another Is electron on the neighbor atom.

    DOI: 10.1088/1742-6596/488/2/022013

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  • Electron reemission processes following photoelectron recapture due to post-collision interaction in inner-shell photoionization of water molecules Reviewed

    Y. Hikosaka, M. Sawa, M. Nakano, K. Soejima, P. Lablanquie, F. Penent, K. Ito

    JOURNAL OF CHEMICAL PHYSICS   138 ( 21 )   2013.6

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    Electron reemission following photoelectron recapture due to post-collision interaction has been studied at 0.7 eV the inner-shell photoionization threshold of water molecules, using a multi-electron coincidence method. Electron reemissions after single Auger decay occur from O and OH fragments which are produced by the dissociations of high-n Rydberg H2O+ states populated through photoelectron recapture. In addition, electron reemissions after double Auger decay are identified in triple coincidence events, where autoionization lines from O and O+ fragments are observed. (C) 2013 AIP Publishing LLC.

    DOI: 10.1063/1.4808028

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  • Single Photon K-2 and K-1K-1 Double Core Ionization in C2H2n (n=1-3), CO, and N-2 as a Potential New Tool for Chemical Analysis Reviewed

    M. Nakano, F. Penent, M. Tashiro, T. P. Grozdanov, M. Zitnik, S. Carniato, P. Selles, L. Andric, P. Lablanquie, J. Palaudoux, E. Shigemasa, H. Iwayama, Y. Hikosaka, K. Soejima, I. H. Suzuki, N. Kouchi, K. Ito

    PHYSICAL REVIEW LETTERS   110 ( 16 )   2013.4

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    We have observed single photon double K-shell photoionization in the C2H2n (n = 1-3) hydrocarbon sequence and in N-2 and CO, using synchrotron radiation and electron coincidence spectroscopy. Our previous observations of the K-2 process in these molecules are extended by the observations of a single photon double photoionization with one core hole created at each of the two neighboring atoms in the molecule (K-1K-1 process). In the C2H2n sequence, the spectroscopy of K-1K-1 states is much more sensitive to the bond length than conventional electron spectroscopy for chemical analysis spectroscopy based on single K-shell ionization. The cross section variation for single photon K-1K-1 double core ionization in the C2H2n sequence and in the isoelectronic C2H2, N-2 and CO molecules validates a knockout mechanism in which a primary ionized 1s photoelectron ejects another 1s electron of the neighbor atom. The specific Auger decay from such states is clearly observed in the CO case. DOI: 10.1103/PhysRevLett.110.163001

    DOI: 10.1103/PhysRevLett.110.163001

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  • Communication: Formation of slow electrons in the Auger decay of core-ionized water molecules Reviewed

    Y. Hikosaka, K. Yamamoto, M. Nakano, T. Odagiri, K. Soejima, I. H. Suzuki, P. Lablanquie, F. Penent, K. Ito

    JOURNAL OF CHEMICAL PHYSICS   137 ( 19 )   2012.11

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

    Double Auger decay of O1s(-1) and its satellite states in H2O has been studied with a multi-electron coincidence method, and a process leading to autoionizing O* fragments has been revealed. The breaking of the two O-H bonds producing the autoionizing O* fragments occurs for highly excited H2O2+ populated by the initial Auger decay. The O* fragments are more favorably produced in the decay from the satellite states, resulting from the larger population of highly excited H2O2+ states inheriting the valence excitation in the initial state. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768213]

    DOI: 10.1063/1.4768213

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  • Auger decay of Ar 2p satellite states studied with a multielectron coincidence method Reviewed

    M. Nakano, Y. Hikosaka, P. Lablanquie, F. Penent, S-M Huttula, I. H. Suzuki, K. Soejima, N. Kouchi, K. Ito

    PHYSICAL REVIEW A   85 ( 4 )   2012.4

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    The Auger decay channels of the Ar 2p satellite states have been investigated using a multielectron coincidence technique, using a magnetic bottle time-of-flight electron spectrometer. For the Ar+(2p(-1)3p(-1)np) satellite states the 2p hole is filled first, while for the Ar+(2p(-1)3s(-1)4s) satellite states the 3s hole is filled first with leading to Ar2+(2p(-1)3p(-1)) states, which subsequently undergo an Auger decay leading to the filling of the 2p hole.

    DOI: 10.1103/PhysRevA.85.043405

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  • Single-Photon Core Double Ionization in Molecules. Reviewed

    P. Lablanquie, F. Penent, J. Palaudoux, L. Andric, P. Selles, S. Carniato, K. Bucar, M. Zitnik, M. Huttula, J. H. D. Eland, E. Shigemasa, K. Soejima, Y. Hikosaka, I. H. Suzuki, M. Nakano, K. Ito

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

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    Single photon double K-shell ionization of small molecules (N-2, O-2, CO, CO2) has been observed by coincidence detection of two photoelectrons with two Auger electron and reveals properties of hollow molecules.

    DOI: 10.1088/1742-6596/388/2/022027

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  • Evidence of Single-Photon Two-Site Core Double Ionization of C2H2 Molecules Reviewed

    P. Lablanquie, T. P. Grozdanov, M. Zitnik, S. Carniato, P. Selles, L. Andric, J. Palaudoux, F. Penent, H. Iwayama, E. Shigemasa, Y. Hikosaka, K. Soejima, M. Nakano, I. H. Suzuki, K. Ito

    PHYSICAL REVIEW LETTERS   107 ( 19 )   2011.11

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    We observe the formation in a single-photon transition of two core holes, each at a different carbon atom of the C2H2 molecule. At a photon energy of 770.5 eV, the probability of this 2-site core double ionization amounts to 1.6 +/- 0.4% of the 1-site core double ionization. A simple theoretical model based on the knockout mechanism gives reasonable agreement with experiment. Spectroscopy and Auger decays of the associated double core hole states are also investigated.

    DOI: 10.1103/PhysRevLett.107.193004

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  • Energy Correlation among Three Photoelectrons Emitted in Core-Valence-Valence Triple Photoionization of Ne Reviewed

    Y. Hikosaka, P. Lablanquie, F. Penent, J. Palaudoux, L. Andric, K. Soejima, E. Shigemasa, I. H. Suzuki, M. Nakano, K. Ito

    PHYSICAL REVIEW LETTERS   107 ( 11 )   2011.9

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    The direct observation of triple photoionization involving one inner shell and two valence electrons is reported. The energy distribution of the three photoelectrons emitted from Ne is obtained using a very efficient multielectron coincidence method using the magnetic bottle electron spectroscopic technique. A predominance of the direct path to triple photoionization for the formation of Ne3+ in the 1s2s(2)2p(4) configuration is observed. It is demonstrated that the energy distribution evolves with photon energy and indicates a significant difference with triple photoionization involving only valence electrons.

    DOI: 10.1103/PhysRevLett.107.113005

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  • Decay pathways after Xe 3d inner shell ionization using a multi-electron coincidence technique Reviewed

    I. H. Suzuki, Y. Hikosaka, E. Shigemasa, P. Lablanquie, F. Penent, K. Soejima, M. Nakano, N. Kouchi, K. Ito

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   44 ( 7 )   2011.4

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    Cascade Auger electron emission following Xe 3d photoionization has been investigated using a multi-electron coincidence technique, which utilizes an electron spectrometer of magnetic bottle type. It has been found that the Xe2+ states of the 4p(-1)4d(-1) configuration, formed by the Auger decay of the Xe+ 3d(3/2,5/2)(-1) states, dominantly turn into triply charged states of the 4d(-2)5p(-1)/4d(-2)5s(-1) configurations. The Xe2+ 4s(-1)4d(-1) states, formed by the 3d Auger decay, yield the 4p(-1)4d(-1)5p(-1) states as well as the 4d(-3) states. From the coincidence spectrum among three Auger electrons, it is suggested that the Xe2+ 4p(-1)4d(-1) states give rise to the following cascade processes: 4p(-1)4d(-1) -&gt; 4d(-2)5p(-1) -&gt; 4d(-1)5p(-3).

    DOI: 10.1088/0953-4075/44/7/075003

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  • Properties of Hollow Molecules Probed by Single-Photon Double Ionization Reviewed

    P. Lablanquie, F. Penent, J. Palaudoux, L. Andric, P. Selles, S. Carniato, K. Bucar, M. Zitnik, M. Huttula, J. H. D. Eland, E. Shigemasa, K. Soejima, Y. Hikosaka, I. H. Suzuki, M. Nakano, K. Ito

    PHYSICAL REVIEW LETTERS   106 ( 6 )   2011.2

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    The formation of hollow molecules (with a completely empty K shell in one constituent atom) through single-photon core double ionization has been demonstrated using a sensitive magnetic bottle experimental technique combined with synchrotron radiation. Detailed properties are presented such as the spectroscopy, formation, and decay dynamics of the N-2(2+) K-2 main and satellite states and the strong chemical shifts of double K holes on an oxygen atom in CO, CO2, and O-2 molecules.

    DOI: 10.1103/PhysRevLett.106.063003

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  • Cross Sections for Single electron capture in collisions of N(2+) with He at low energies Reviewed

    K. Soejima, S. Tanaka, A. Danjo

    14TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF HIGHLY CHARGED IONS (HCI 2008)   163   2009

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    The absolute cross sections of single electron capture during the collision of N(2+) with He have been measured over the energy range 0.1-300 eV/u. From the plot showing the dependence of cross sections on energy, the following three remarkable observations can be made: (1) the cross sections exhibit an oscillatory structure below 1eV/u, (2) a bend in the cross sections appears at approximately I eV/u and (3) there is a dip in the cross sections at approximately 70 eV/u. The formation of an oscillatory structure is attributed to the glory effect. The bend in the cross sections occurs owing to the attractive potential part of a 1(2)Pi state of quasimolecule NHe(2+). The dip in the cross sections appears as a result of opening a new reaction path above 70eV/u. The glory effect can be observed for the first time on a total cross section even for slow ion-neutral collisions. The objective of this study is to explore the possibilities of providing a detailed explanation of energy dependence measurements in order to study reaction dynamics for a charge changing process.

    DOI: 10.1088/1742-6596/163/1/012056

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  • Angular distributions of vibrationally-resolved C 1s photoelectrons from fixed-in-space CO molecules: vibrational effect in the shape-resonant C 1s photoionization of CO Reviewed

    J Adachi, K Hosaka, S Furuya, K Soejima, M Takahashi, A Yagishita, SK Semenov, NA Cherepkov

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA   137   243 - 248   2004.7

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    We have measured vibrationally-resolved molecular-frame photoelectron angular distributions (MF-PAD) from the C 1s level of CO molecules in the sigma shape resonance region. The MF-PAD's for vibrational levels (v(f) = 0, 1, and 2) in the C 1s --&gt; epsilonlsigma channel are apparently different one from another at each incident photon energy. These experimental MF-PAD's agree with the present theoretical results from averaging the nuclear distance dependent dipole matrix elements with the relaxed core Hartree-Fock calculations. The results show that the MF-PAD's sensitively depend on the vibrational levels. This means that the internuclear distance dependences of phases and of magnitudes of dipole matrix elements play a crucial role in the C 1s photoionization of CO. (C) 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.elspec.2004.02.043

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  • Elastic scattering of low energy electrons from ozone molecules Reviewed

    T Ono, E Shimaki, Y Kojima, Y Kiyama, T Takahasi, K Soejima, A Danjo

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   73 ( 4 )   892 - 897   2004.4

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    Differential cross sections have been measured for vibrationally elastic scattering of electrons from ozone molecules at incident electron energies from 2 eV to 10 eV in the angular range from 20degrees to 120degrees. Absolute values of the differential cross sections have been obtained by means of the relative flow method. Integral and momentum transfer cross sections have been derived from the measured data by extrapolating to 0degrees and 180degrees scattering angles. Comparison was made between the present measurements and those from other experiments and theoretical calculations.

    DOI: 10.1143/JPSJ.73.892

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  • Shape-resonance-enhanced vibrational effects in the angular distributions of C 1s photoelectrons from fixed-in-space CO molecules Reviewed

    J Adachi, K Hosaka, S Furuya, K Soejima, M Takahashi, A Yagishita, SK Semenov, NA Cherepkov

    PHYSICAL REVIEW LETTERS   91 ( 16 )   2003.10

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    Angular distributions of C 1s photoelectrons from fixed-in-space CO molecules have been measured with vibrational resolution. A strong dependence of the angular distributions on the vibrational states of the residual molecular ion has been found for the first time in the region of the shape resonance. Calculations in the relaxed core Hartree-Fock approximation have reproduced the angular distributions fairly well in the general shapes of the angular distributions due to the correct description of nuclear motion as an average of the internuclear-distance-dependent dipole amplitudes.

    DOI: 10.1103/PhysRevLett.91.163001

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  • Complete photoionization experiment in the region of the 2 delta(g) -&gt; delta(u) shape resonance of the N(2) molecule Reviewed

    S Motoki, J Adachi, K Ito, K Ishii, K Soejima, A Yagishita, SK Semenov, NA Cherepkov

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   35 ( 18 )   3801 - 3819   2002.9

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    Angular distributions of photoelectrons (ADPs) from the 2sigma(g) shell of a fixed-in-space N(2) molecule have been measured for left- and right-elliptically polarized, as well as for linearly polarized, light. From these data a set of dipole matrix elements and phase shift differences characterizing the process has been determined taking into account the acceptance angles of both electron and ion detectors, i.e. the complete experiment has been performed. Good agreement between the experimental and the relevant theoretical values calculated in the random phase approximation is obtained. Based on the results of the complete experiment, three-dimensional ADPs and ions are predicted for different light polarizations.

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  • Double photoionization of helium at an excess energy of 60 eV using left- and right-elliptically-polarized light Reviewed

    SA Collins, S Cvejanovic, C Dawson, TJ Reddish, DP Seccombe, A Huetz, L Malegat, P Selles, AK Kazansky, A Danjo, K Soejima, K Okuno, A Yagishita

    PHYSICAL REVIEW A   65 ( 5 )   2002.5

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    Helium double photoionization (gamma,2e) triple differential cross sections (TDCSs) were measured at an excess energy of 60 eV using a dual toroidal spectrometer and synchrotron radiation from a helical undulator (BL-28A, Photon Factory, Japan). Energy-sharing ratios (R=E-2/E-1) for the two ejected electrons of 5 and 11 are studied with both right- and left-handed elliptically polarized light. The TDCSs are found to be in good agreement with those obtained using the hyperspherical R matrix with semiclassical outgoing waves theory. The circular dichroism for a limited mutual angular range (phi(12)approximate to110degrees-200degrees) is determined from the experimental data for both R=5 and 11, and compared to theoretical calculations performed over the complete range of mutual angles. No dynamic nodes are found in either the experimental (within the explored phi(12) range) or theoretical circular dichroism for these R values at this excess energy.

    DOI: 10.1103/PhysRevA.65.052717

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  • Direct probe of the shape resonance mechanism in 2 sigma(g)-shell photoionization of the N-2 molecule Reviewed

    S Motoki, J Adachi, K Ito, K Ishii, K Soejima, A Yagishita, SK Semenov, NA Cherepkov

    PHYSICAL REVIEW LETTERS   88 ( 6 )   2002.2

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    Angular distributions of photoelectrons from a 2sigma g shell of fixed-in-space N-2 molecules have been measured for left- and right-elliptically polarized and for linearly polarized light at several photon energies in the region of sigma* shape resonance. That allowed the determination of a set of dipole matrix elements and phase shift differences characterizing the process. These data clearly show the enhancement of the f sigma(u) partial cross section in the resonance simultaneously with an abrupt increase of the corresponding phase shift by pi, which is the first experimental demonstration of the nature of the sigma* shape resonance in homonuclear diatomic molecules.

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  • Chiral electron pairs in photodouble ionization of helium Reviewed

    K Soejima

    CORRELATIONS, POLARIZATION, AND IONIZATION IN ATOMIC SYSTEMS   604   178 - 183   2002

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    Triple differential cross sections (TDCSs) of tile two ejected chiral electrons from helium were measured for several kinematic conditions using circularly polarized synchrotron radiation at tile Photon Factory. The selected kinematic conditions were E=9 eV (R=2,8), E=40 eV (R=7, 19) and E=50 eV (R=24), where E is the excess energy and R is the ratio of the kinetic energy of the ejected electrons. The changes in the TDCSs with "E" and "R" are presented. The gerade (a(g)) and ungerade (a(u)) dipole amplitudes were determined using four parameters parametrization. The "E" and "R" dependences of the four parameters of a(g) and a(u) arc also presented.

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  • Direct Probe of the Shape Resonance Mechanism in [Formula presented]-Shell Photoionization of the [Formula presented] Molecule Reviewed

    S. Motoki, J. Adachi, A. Yagishita, J. Adachi, K. Ito, A. Yagishita, N. A. Cherepkov, K. Ishii, K. Soejima, S. K. Semenov, N. A. Cherepkov

    Physical Review Letters   88 ( 6 )   4   2002

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    Angular distributions of photoelectrons from a [Formula presented] shell of fixed-in-space [Formula presented] molecules have been measured for left- and right-elliptically polarized and for linearly polarized light at several photon energies in the region of [Formula presented] shape resonance. That allowed the determination of a set of dipole matrix elements and phase shift differences characterizing the process. These data clearly show the enhancement of the [Formula presented] partial cross section in the resonance simultaneously with an abrupt increase of the corresponding phase shift by [Formula presented], which is the first experimental demonstration of the nature of the [Formula presented] shape resonance in homonuclear diatomic molecules. © 2002 The American Physical Society.

    DOI: 10.1103/PhysRevLett.88.063003

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  • Triply differential cross-section measurements in the double photoionization of D-2 and He with asymmetric kinematic conditions Reviewed

    SA Collins, A Huetz, TJ Reddish, DP Seccombe, K Soejima

    PHYSICAL REVIEW A   64 ( 6 )   2001.12

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    The breakup of D-2 following the absorption of a single photon, leading to four free charged particles interacting via the Coulomb force, has been investigated. Triply differential cross sections (TDCSs) of the two ejected electrons were measured for selected asymmetric kinematic conditions, namely, a 20 eV electron in coincidence with a 5 eV "reference" electron fixed at four different angles. The results are compared with helium TDCSs and, although the respective angular distributions have similar features, there are surprising differences that could have their origin in two-center interference effects.

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  • K-shell photoionization of CO: I. Angular distributions of photoelectrons from fixed-in-space molecules Reviewed

    S Motoki, J Adachi, Y Hikosaka, K Ito, M Sano, K Soejima, A Yagishita, G Raseev, NA Cherepkov

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   33 ( 20 )   4193 - 4212   2000.10

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    Angular distributions of photoelectrons from both C and O K-shells of the fixed-in-space CO molecule have been measured using the angle-resolved photoeletron-photoion coincidence technique. The measurements have been performed at several photon energies from the ionization thresholds up to about 30 eV above them, where the sigma* shape resonances occur. Experimental results are compared with the multiple-scattering calculations of Diil et al (1976 J. Chem. Phys. 65 3158) and with our new calculations in the relaxed-core Hartree-Fock approximation. Our calculations are in a better agreement with the experimental data though numerical discrepancies remain. The experimental angular distributions are fitted by the expansion in Legendre polynomials containing up to ten terms and the extracted parameters are compared with the corresponding theoretical values.

    DOI: 10.1088/0953-4075/33/20/301

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  • K-shell photoionization of CO: II. Determination of dipole matrix elements and phase differences Reviewed

    NA Cherepkov, G Raseev, J Adachi, Y Hikosaka, K Ito, S Motoki, M Sano, K Soejima, A Yagishita

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   33 ( 20 )   4213 - 4236   2000.10

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    Using the experimental angular distributions of photoelectrons from the K-shells of an oriented CO molecule reported in a companion paper, we have performed a so-called complete experiment and determined 18 dynamical parameters (ten moduli of transition moments and eight phase differences) for the O K-shell, and 16 dynamical parameters (nine moduli of transition moments and seven phase differences) for the C K shell, and compared them with the results of our calculations in the relaxed-core Hartree-Fock (RCHF) approximation. The agreement between theory and experiment is only qualitative, therefore the model has to be improved by including electron correlations. From the analysis of experimental data we proved that the sigma* shape resonance is due to not only the f-wave, as was widely believed earlier, but is due to approximately equal contributions of three partial waves with 1 less than or equal to l less than or equal to 3 for the C R-shell, and four partial waves with 0 less than or equal to l less than or equal to 3 for the O K-shell, with a rather substantial contribution of other partial waves with I less than or equal to 5. From the analysis of the transition moments determined from the experiment it follows that several Cooper minima are likely to exist in partial photoionization cross sections, in particular, in the C 1s sigma --&gt; epsilons sigma and in the O 1s sigma --&gt; epsilond sigma transitions.

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  • Photoelectron angular distributions from dissociative photoionization channels of fixed-in-space molecular hydrogen Reviewed

    K Ito, J Adachi, R Hall, S Motoki, E Shigemasa, K Soejima, A Yagishita

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   33 ( 3 )   527 - 533   2000.2

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    The angular distribution of photoelectrons from fixed-in-space molecular hydrogen has been measured in the 44-76 eV photon energy range for an ionic state, with a state energy of 38 eV measured from the H-2 ground state, dissociating to H+ + H(n = 2). The photoelectrons are ejected nearly isotropically at 44 eV when their energy is relatively low, while ejection perpendicular to the molecular axis becomes more and more favoured as the photon energy increases. This behaviour is possibly explained in terms of direct photoionization to the 2p pi(u), and 2s sigma(g) states of H-2(+); the former being favoured at 44 eV, and the latter at photon energies far from threshold.

    DOI: 10.1088/0953-4075/33/3/320

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  • Circular dichroism of angular correlation patterns in two-step and direct double photoionization Reviewed

    K Soejima

    PHYSICS OF ELECTRONIC AND ATOMIC COLLISIONS   500   136 - 145   2000

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    Angular correlation patterns of N-5-O23O23 S-1(0) Auger electrons in coincidence with 4d(5/2) photoelectrons in two-step double photoionization of xenon and those of two emitted photoelectrons in coincidence with each other in direct double photoionization of helium have been studied with elliptically polarized photons. Circular dichroism in the angular distribution patterns has been reported in both cases.

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  • Dynamic properties of N and O 1s(-1) sigma u* shape resonances in N-2 and CO2 molecules Reviewed

    AA Pavlychev, NG Fominykh, N Watanabe, K Soejima, E Shigemasa, A Yagishita

    PHYSICAL REVIEW LETTERS   81 ( 17 )   3623 - 3626   1998.10

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    An essential correlation between intramolecular interference of photoelectron waves and core-hole molecular relaxation is revealed by analyzing the partial wave composition of the calculated angular distribution of photoelectrons in the N and O 1s(-1)sigma(u)* shape resonances of aligned N-2 and CO2. The dominance of coherent (N-2) and incoherent (CO2) interference is revealed, pf and spd hybridization controls the main direction of photoelectron emission from the N and O K shell, respectively. [S0031-9007(98)07498-5].

    DOI: 10.1103/PhysRevLett.81.3623

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  • High-resolution spherical grating monochromator for the undulator beamline (BL-16B) at the Photon Factory Reviewed

    E Shigemasa, A Toyoshima, YL Yan, T Hayaishi, K Soejima, T Kiyokura, A Yagishita

    JOURNAL OF SYNCHROTRON RADIATION   5   777 - 779   1998.5

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    The design and performance of a 24 m high-resolution spherical grating monochromator (H-SGM) for the undulator beamline (BL-16B) at the Photon Factory are described. With three interchangeable gratings of 400, 900 and 2000 lines mm(-1), the H-SGM is designed to cover the photon energy range 40-600 eV. With a resolving power of approximately 2000 in the photon energy range 40-530 eV, more than 10(11) photons s(-1) have been measured. The best resolutions obtained so far, at a substantially lower photon flux, are greater than 10 000 at 250 eV and 8000 at 400 eV.

    DOI: 10.1107/S0909049597019791

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  • First observation of circular dichroism in angular correlation patterns for two-step double and direct double photoionization of xenon Reviewed

    K Soejima, M Shimbo, A Danjo, K Okuno, E Shigemasa, A Yagishita

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   32 ( 3 )   368 - 372   1998.3

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    Angular correlation patterns of N-5-O23O23 S-1(0) Auger electrons in coincidence with 4d(5/2) photoelectrons in the two-step double photoionization of xenon and those of two outgoing 5p photoelectrons in coincidence with each other in the direct double photoionization of xenon were measured with a circularly polarized photon beam from a helical undulator. Circular dichroism was clearly observed in both cases. For the two-step process, the experimental data were in good agreement with the theoretical prediction based on the two-step model.

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  • Mini-EBIS report on electron capture in slow collisions of multiply charged ions with neutral targets Reviewed

    K Okuno, H Saitoh, K Soejima, SD Kravis, N Kobayashi

    PHYSICA SCRIPTA   T71   140 - 146   1997

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    The status of cross section measurements carried out with a Mini-EBIS- is reported, here. Single- and multiple-electron transfer processes in collisions of Arq+ (q = 6, 7, 8, 9, and 11) with H-2 and He, and those of C4+ with Ne, Ar and Kr have been investigated at low energies ranging from 0.075 eV/amu to 275 eV/amu and from 0.33 eV/amu to 667 eV/amu, respectively. All data of single-electron transfer cross sections measured for Arq+ -H-2 and -He systems shows a similar tendency to converge toward the Langevin cross section at the low energy end. In the C4+ -Ne system, double-electron transfer is predominant at high energies and it is dominated by the backward scattering at low energies. From the observation of recoil ions produced in C4+ -Ar and -Kr collisions, it is found that the angular distribution of the multiple-electron transfer collisions shifts toward the backward direction in the center-of-mass frame with decreasing collision energy and four-electron transfer processes take place. The importance of the orbiting effect due to the polarization force and the backward scattering are enhanced in the single- and multiple-electron transfer collisions of highly charged ions at low energies.

    DOI: 10.1088/0031-8949/1997/T71/026

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  • Molecular shape resonances studied by Angle-resolved PEPICO Reviewed

    E. Shigemasa, J. Adachi, N. Watanabe, K. Soejima, A. Yagishita

    Eds. A. Yagishita and T. Sasaki: Atomic and Molecular Photoionization, Universal Academy Press, INC.   69 - 78   1996

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  • Measurements of charge transfer cross sections for Ar-q+ (q=6, 7, 8, 9 and 11) collisions with He and H-2 targets at low energies Reviewed

    K Okuno, H Saitoh, K Soejima, S Kravis, N Kobayashi

    PHYSICS OF ELECTRONIC AND ATOMIC COLLISIONS   ( 360 )   867 - 876   1995

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  • SINGLE AND DOUBLE-CHARGE-EXCHANGE CROSS-SECTIONS FOR ARQ++H(2) (Q=6,7 AND 8) FROM 6EV TO 8KEV Reviewed

    S KRAVIS, M OURA, Y AWAYA, K OKUNO, H SAITOH, K SOEJIMA, Y KANEKO

    6TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF HIGHLY CHARGED IONS   274   128 - 131   1993

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  • 近赤外フェムト秒レーザーイオン化によるMALDIプルーム組成の解明および「準熱平衡モデル」に基づく数値シミュレーション

    城田起郎, 柘植雅士, 彦坂泰正, 副島浩一, 星名賢之助

    質量分析総合討論会講演要旨集   65th   198   2017.5

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  • 9pAT-1 Metastable dication formation following inner-shell ionization of CO_2

    Hikosaka Y., Shibata Y., Soejima K., Iwayama H., Shigemasa E.

    Meeting abstracts of the Physical Society of Japan   69 ( 2 )   87 - 87   2014.8

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  • フェムト秒レーザーイオン化によるMALDIプルーム中の中性種の検出

    城田起郎, 城田起郎, 彦坂泰正, 副島浩一, 星名賢之助

    分子科学討論会講演プログラム&amp;要旨(Web)   8th   ROMBUNNO.1P019 (WEB ONLY)   2014

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  • 25aGL-6 Double core hole states of molecules using a multi-electron coincidence technique

    Nakano M., Hikosaka Y., Odagiri T., Suzuki I. H., Soejima K., Lablanquie P., Penent F., Kouchi N., Ito K.

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   160 - 160   2011.3

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  • 25aRA-4 Charge transfer processes of multiply charged ions at low energies : III. W^<q+>-He(q=4.5.6)

    Sato M., Kato C., Hikosaka Y., Soejima K.

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   164 - 164   2011.3

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  • 25aGL-7 Study of the decay process of core-hole states in H_2O using a multi-electron coincidence technique

    Yamamoto K., Hikosaka Y., Soejima K., Nakano M., Odagiri T., Suzuki I., Ito K.

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   160 - 160   2011.3

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  • 23pTC-6 Electron emission from Xe 3d Auger final states using a multi-electron coincidence technique

    Suzuki I. H., Hikosaka Y., Shigemasa E., Soejima K., Nakano M., Lablanquie P., Penent F., Ito K.

    Meeting abstracts of the Physical Society of Japan   65 ( 1 )   218 - 218   2010.3

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  • 30aSL-5 Charge transfer processes of multiply charged ions at low energies : I. F^<q+>(2,3,4)-He

    Soejima K., Toida K., Danjo A.

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   183 - 183   2009.3

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  • 27pXN-7 Vibrational effects in molecule-frame photoelectron angular distributions on the core-level shape resonances

    Adachi J., Hosaka K., Furuya S., Soejima K., Takahashi M., Yagishita A., Semenov Sergei K., Cherepkov Nikolai A.

    Meeting abstracts of the Physical Society of Japan   59 ( 1 )   157 - 157   2004.3

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  • Direct probe of the shape resonance mechanism in 2 sigma(g)-shell photoionization of the N-2 molecule

    S Motoki, J Adachi, K Ito, K Ishii, K Soejima, A Yagishita, SK Semenov, NA Cherepkov

    PHYSICAL REVIEW LETTERS   88 ( 6 )   1   2002.2

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    Angular distributions of photoelectrons from a 2sigma g shell of fixed-in-space N-2 molecules have been measured for left- and right-elliptically polarized and for linearly polarized light at several photon energies in the region of sigma* shape resonance. That allowed the determination of a set of dipole matrix elements and phase shift differences characterizing the process. These data clearly show the enhancement of the f sigma(u) partial cross section in the resonance simultaneously with an abrupt increase of the corresponding phase shift by pi, which is the first experimental demonstration of the nature of the sigma* shape resonance in homonuclear diatomic molecules.

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  • He原子の光二重電離‐カイラル電子対の生成‐

    副島 浩一, 柳下 明

    日本物理学会   57 ( 6 )   408 - 412   2002

  • Perfect experiments on photoionization by 2og photoelectron angular distributions from oriented N_2 molecules

    Yagishita A., Motoki S., Adachi J., Ito K., Ishii K., Soejima K.

    Meeting abstracts of the Physical Society of Japan   56 ( 1 )   121 - 121   2001.3

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  • Photoelectron angular distributions from OK shell of oriented CO molecules: A critical comparison between theory and experiment

    K Ito, J Adachi, Y Hikosaka, S Motoki, K Soejima, A Yagishita, G Raseev, NA Cherepkov

    PHYSICAL REVIEW LETTERS   85 ( 1 )   46 - 49   2000.7

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    The dynamical information (ten dipole matrix elements and eight phase differences) has been deduced from the measured angular distributions of photoelectrons from O K shell of oriented CO molecules near the ionization threshold in the region of a sigma* shape resonance. Light polarization parallel and perpendicular to the molecular axis has been used. An important contribution of six l sigma partial waves with 0 less than or equal to l less than or equal to 5 to the sigma* shape resonance is demonstrated. A comparison with our calculations in the relaxed core Hartree-Fock approximation reveals only a qualitative agreement, therefore a more advanced theory is needed.

    DOI: 10.1103/PhysRevLett.85.46

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  • COMPLETE EXPERIMENT IN O K-SHELL PHOTOIONIZATION OF CO

    Motoki S., Adachi J., Hikosaka Y., Ito K., Soejima K., Sano M., Yagishita A., Raseev G., Cherepkov N. A.

    Meeting abstracts of the Physical Society of Japan   55 ( 1 )   107 - 107   2000.3

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  • 二重光電離過程にあらわれる円二色性

    日本放射光学会   13 ( 1 )   40   2000

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  • Experimental and theoretical study of linear and circular dichroism in helium double photoionization

    A Kheifets, Bray, I, K Soejima, A Danjo, K Okuno, A Yagishita

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   32 ( 17 )   L501 - L509   1999.9

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    The fully resolved triply differential cross section (TDCS) of helium double photoionization with elliptically polarized light has been determined, both experimentally and theoretically, at the photon energy of 88 eV. The excess energy was shared between the photoelectron pair as 1 + 8, 3 + 6 and 4.5 + 4.5 eV. Simultaneous sign reversal of the Stokes parameters S-1, S-3 resulted in a profound change of shape of the TDCS. This effect can be attributed to the linear dichroism in the case of equal energy sharing, and a combination of the circular and linear dichroisms in the case of unequal energy sharing. Theoretical TDCS was obtained by employing the convergent close-coupling (CCC) method. In contrast to the previous work of Mergel et al (1998 Phys. Rev. Lett. 80 5301) who investigated the circular dichroism at 99 eV photon energy, good agreement is found between experimental and calculated TDCS in all cases.

    DOI: 10.1088/0953-4075/32/17/104

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  • Linear and circular dichroism in the double photoionization of helium

    K Soejima, A Danjo, K Okuno, A Yagishita

    PHYSICAL REVIEW LETTERS   83 ( 8 )   1546 - 1549   1999.8

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    Energy- and angle-resolved triply differential cross sections have been measured in the double photoionization of helium under equal and unequal energy sharing conditions using right- and left-elliptically polarized photons. Linear dichroism in these cross sections has been observed under the equal energy sharing. For the unequal energy sharing a pure circular polarization effect has been deduced by eliminating the linear polarization contribution.

    DOI: 10.1103/PhysRevLett.83.1546

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  • 29a-ZC-7 Angular Distributions of Photoelectrons from Fixed-in-space CO Molecules

    Motoki S., Hikosaka Y., Sano M., Soejima K., Adachi J., Yagishita A., Ito K.

    Meeting abstracts of the Physical Society of Japan   54 ( 1 )   750 - 750   1999.3

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  • 29a-ZC-6 Molecular vibrational effect in the O-ls photoelectron angular distribution of CO_2 inner shell ionization

    Ito K., Hikosaka Y., Motoki S., Sano M., Watanabe N., Shigemasa E., Soejima K., Adachi J., Yagishita A.

    Meeting abstracts of the Physical Society of Japan   54 ( 1 )   750 - 750   1999.3

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  • Angular Distributions of photoelectrons from Fixed-in space CO Molecules for the Parallel Transitions

    MOTOKI Sohei, HIKOSAKA Yasumasa, FUJITA Yoshihiro, ADACHI Jun-ichi, SANO Mutsumi, SOEJIMA Kou-ichi, YAGISHITA Akira, ITO Kenji

    24   110 - 110   1998.11

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  • Dissociation of N_2 molecules in slow collisions between Ar^<9+> ions and N_2 molecules

    OGUMA Y., KONUMA Y., ONO T., KOJIMA Y., NISHIMURA A., YAMAGUTI T., SOEJIMA K., DANJO A., YOSHINO M.

    Meeting abstracts of the Physical Society of Japan   53 ( 2 )   888 - 888   1998.9

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  • Circular and linear dichroism for direct double photoionization of He

    SOEJIMA K., OGUMA Y., DANJO A., OKUNO K., TAGISHITA A.

    Meeting abstracts of the Physical Society of Japan   53 ( 2 )   872 - 872   1998.9

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  • Angular Distribution of Photoelectrons from Fixed-in-space CO Molecules (I) Parallel Transition

    MOTOKI Sohei, HIKOSAKA Yasumasa, FUJITA Yoshihiro, ADACHI Jun-ichi, SANO Mutsumi, SOEJIMA Kou-ichi, YAGISHITA Akira, ITO Kenji

    Meeting abstracts of the Physical Society of Japan   53 ( 2 )   873 - 873   1998.9

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  • First observation of circular dichroism in angular correlation patterns for two-step double and direct double photoionization of xenon

    K Soejima, M Shimbo, A Danjo, K Okuno, E Shigemasa, A Yagishita

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   32 ( 3 )   368 - 372   1998.3

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    Angular correlation patterns of N-5-O23O23 S-1(0) Auger electrons in coincidence with 4d(5/2) photoelectrons in the two-step double photoionization of xenon and those of two outgoing 5p photoelectrons in coincidence with each other in the direct double photoionization of xenon were measured with a circularly polarized photon beam from a helical undulator. Circular dichroism was clearly observed in both cases. For the two-step process, the experimental data were in good agreement with the theoretical prediction based on the two-step model.

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  • Direct determination of partial wave contributions in the sigma* shape resonance of CO molecules

    E Shigemasa, J Adachi, K Soejima, N Watanabe, A Yagishita, NA Cherepkov

    PHYSICAL REVIEW LETTERS   80 ( 8 )   1622 - 1625   1998.2

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    The first complete experiment for the C K-shell of CO molecules in the region of the sigma* shape resonance has been performed by detecting photoelectrons in coincidence with fragment ions. Four ratios of dipole matrix elements and four phase shift differences have been extracted from the experi mental data. Their analyses show that, in the sigma* shape resonance due to the l mixing, d and f partial waves give the main contribution to the cross section, and f and g waves give the main contribution to a rapid increase of phase shift by pi.

    DOI: 10.1103/PhysRevLett.80.1622

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  • Fixed-molecule 1s sigma(g,u) photoelectron angular distributions as a probe of sigma(g)* and sigma(u)* shape resonances of CO2

    N Watanabe, J Adachi, K Soejima, E Shigemasa, A Yagishita, NG Fominykh, AA Pavlychev

    PHYSICAL REVIEW LETTERS   78 ( 26 )   4910 - 4913   1997.6

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    Angular distributions of 1s sigma(g,u), photoelectrons from CO2 molecules, oriented parallel to the electric vector of incident light, have been measured. The angular distribution patters at sigma(g)* and sigma(u)* shape resonances are significantly different. From those expected in the virtual molecular orbitals concept. The analyses of the patterns have made it clear that the mixing of outgoing photoelectron partial waves and the interference between them are responsible for the observed patterns, unlike N-2 photoionization. Calculations based on a quasiatomic model bare reproduced the observed patterns fairly well.

    DOI: 10.1103/PhysRevLett.78.4910

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  • First observation of circular dichroism in angular correlation patterns for two-step and direct double photoionization of xenon(共著)

    Journal of Korean Physical Society   1997

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  • Experimental evidence of the d and f waves predominant contribution to the σ<sup>*</sup> shape resonance in CO molecules(共著)

    Physical Review Letters   1997

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  • Circular dichroism in fragmentation patterns for two-step double photoionization of Xe

    K Soejima, M Shimbo, A Danjo, K Okuno, E Shigemasa, A Yagishita

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   29 ( 9 )   L367 - L371   1996.5

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    The angular correlation between 4d(5/2) photo- and N-5-O23O23 S-1(0) Anger electrons in xenon has been measured for right and left circularly polarized light with 110 eV energy. Thanks to the high degree of circular polarization of the helical undulator radiation, the circular dichroism in the angular correlation has been clearly observed.

    DOI: 10.1088/0953-4075/29/9/003

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  • 30p-YA-4 Charge transfer reactions of low energy multiply charged ions XIV.

    Saitoh H., Suzuki K., Soejima K., Okuno K., Kobayashi N.

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1995 ( 4 )   61 - 61   1995.9

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  • 27p-YA-6 Circular dicroism in inner-shell photoionization of Xe

    Soejima K., Shimbo M., Danjo A., Okuno K., Shigemasa E., Yagishita A.

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1995 ( 4 )   24 - 24   1995.9

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  • SINGLE-CHARGE-EXCHANGE AND DOUBLE-CHARGE-EXCHANGE CROSS-SECTIONS FOR AR-Q++H-2 (Q=6, 7, 8, 9, AND 11) COLLISIONS FROM 6 EV TO 11 KEV

    S KRAVIS, H SAITOH, K OKUNO, K SOEJIMA, M KIMURA, SHIMAMURA, I, Y AWAYA, Y KANEKO, M OURA, N SHIMAKURA

    PHYSICAL REVIEW A   52 ( 2 )   1206 - 1212   1995.8

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    The cross sections for single-electron capture, including transfer ionization, and for double-electron capture, have been measured for Ar-q+ + HL for q = 6, 7, 8, 9, and 11 with projectile energies from q eV to q keV. Theoretically, the cross sections for Ar6+ and Ar8+ impact were calculated using a molecular-orbital expansion method in the energy region from 240 eV to 80 keV, and are in good agreement with experiment. The single-electron-capture cross sections were found to be more than one order of magnitude larger than those for double capture in both experiment and theory. The single-electron-capture cross sections were also compared to the Langevin cross section, a scaling law developed by Muller and Salzborn [Phys. Lett. 62A, 391 (1977)], and the absorbing sphere model.

    DOI: 10.1103/PhysRevA.52.1206

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  • Charge transfer reactions of low energy multiply charged ions XIII. C^<4+>+Ne. Ar, Kr

    Saitoh H., Soejima K., Okuno K., Kobayashi N.

    Abstracts of the meeting of the Physical Society of Japan. Annual meeting   50 ( 4 )   26 - 26   1995.3

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  • Mini-EBIS reports on slow electron capture collisions of multiply charged ions(共著)

    Physica Scripta   T59   440   1995

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  • 4p-L-7 Coincedence experiments of Xe 4d photoelectron with Augre electron

    Soejima K, Shimbo M, Okuno K, Danjo A, Shigemasa E, Yagishita A

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1994 ( 4 )   57 - 57   1994.8

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  • 4a-L-2 Charge transfer reactions of low energy multiply charged ions XII Ar^<q+>+N_2(q=6, 7, 8)

    Saitho H, Soejima K, Okuno K, Kobayashi N

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1994 ( 4 )   48 - 48   1994.8

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  • 30p-F-9 Charge transfer reactions of low energy multiply charged ions XI(C^<4+>+Ar, Kr)

    Saitoh H, Soejima K, Okuno K, Kobayashi N

    Abstracts of the meeting of the Physical Society of Japan. Annual meeting   49 ( 4 )   54 - 54   1994.3

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  • 30a-L-9 Charge Transfer Reactions of Low Energy Multiply Charged Ions IX. : C^<4+>+Ar Collisions

    Soejima K., Saitou H., Okuno K., Kaneko Y.

    Abstracts of the meeting of the Physical Society of Japan. Annual meeting   48 ( 4 )   39 - 39   1993.3

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  • Multi‐electron‐capture processes by C4+ from CH4, C2H6, C3H8 and n‐C4H10 in the energy range 0.7–400 eV u−1

    K. Soejima, K. Okuno, Y. Kaneko

    Organic Mass Spectrometry   28 ( 4 )   344 - 348   1993

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    Charge‐changing cross‐sections σ43, σ42 and σ41 of C4+ injected into CH4, C2H6, C3H8 and n‐C4H10 were measured in the energy range 0.7–400 eV u−1. A tandem mass spectrometer system with an ion source of the EBIS type (Mini‐EBIS) and a collision cell consisting of an octupole ion beam guide was used. It is a significant feature that both the magnitude and energy dependence of the cross‐sections obtained showed very little target dependence for all the hydrocarbon targets studied. Another feature is that σ41 is very close to σ42, and they become flat at low energy, in contrast to the case with an argon target which was studied as a reference. This implies that multi‐electron‐capture processes become dominant in low‐energy collisions with hydrocarbon molecules. Copyright © 1993 John Wiley &amp
    Sons Ltd.

    DOI: 10.1002/oms.1210280414

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  • 27a-ZK-2 Charge Transfer Reactions of Low Energy Multiply Charged Ions in Ar^<2+>-H_2 Collisions

    Okuno K, Kravis S.D., Saito H, Soejima K, Kaneko Y

    1992 ( 4 )   40 - 40   1992.9

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  • CROSS-SECTIONS FOR SINGLE AND MULTIPLE ELECTRON-CAPTURE IN LOW-ENERGY COLLISIONS OF C-4+ WITH H-2, O-2 AND N-2

    K SOEJIMA, CJ LATIMER, K OKUNO, N KOBAYASHI, Y KANEKO

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   25 ( 13 )   3009 - 3014   1992.7

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    Cross sections for single and multiple electron capture in collisions of C4+ with H-2, N2 and O2 have been measured within the energy range 0.33-666 eV amu-1. Where comparison is possible, the results are in good agreement with previous measurements at higher energies. Below 100 eV amu-1 there are significant differences between experiment and the currently available theories.

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  • 28a-S-10 Charge Transfer Reactions of low Energy Multiply Charged Ions VI. In C^<4+>-H_2, N_2, O_2 Collisions.

    Soejima K., Latimer C.J., Okuno K., Kobayashi N., Kaneko Y.

    47 ( 4 )   40 - 40   1992.3

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  • Single-and double-electron capture in <sup>3</sup>He<sup>2+</sup>-H<sub>2</sub> collisions at low energy from 1 to 2000eV(共著)

    Journal of Physics B, Atomic, Molecular and Optical Physics   25 ( 4 )   L105 - L108   1992

  • 30a-Q-2 Charge Changing Reactions of Low Energy Multiply Charged lons V.I^<q+>+He(q=24,25,26)collisions

    Soejima K., Okuno K., Kaneko Y.

    46 ( 4 )   49 - 49   1991.9

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  • APPLICATION OF MINI-EBIS TO CROSS-SECTION MEASUREMENTS OF SINGLE AND DOUBLE ELECTRON-CAPTURE IN LOW-ENERGY COLLISIONS OF C-4+, N-4+ AND O-4+ WITH HE

    K OKUNO, K SOEJIMA, Y KANEKO

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   53 ( 4 )   387 - 394   1991.4

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    A small size electron beam ion source (mini-EBIS) cooled with liquid nitrogen has been developed for atomic collision research. An experimental technique using mini-EBIS in combination with an octupole ion beam guide (OPIG) has proved very useful for low energy collision experiments including highly charged ions. Single and double electron capture cross sections in collision systems of C4+ -He, N4+ -He and O4+ -He have been measured at low energies from 0.5 to 2000 eV in the center of mass system.

    DOI: 10.1016/0168-583X(91)95414-9

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  • 2a-N-6 Charge Transfer Reactions of Low Energy Multiply Charged IonIV : ^3He^<2+>+He,H_2 Collisions

    Soejima K., Okuno K., Kaneko Y.

    1990 ( 4 )   27 - 27   1990.9

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  • Charge Transfer Reactions Of Low Energy Multiply Charged Ions.III. : O^<4+>-He Collisions.

    Soejima K., Okuno K., Kaneko Y.

    45 ( 4 )   51 - 51   1990.3

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  • 4a-ZG-9 Charge Transfer Reactions of Low Energy Multiply Charged Ions

    Sojima K., Okuno K., Kaneko Y.

    1989 ( 4 )   42 - 42   1989.9

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  • 28a-R-11 Charge Transfer Reactions of Low Energy Multiply Charged Ions : I. In C^<4+>-He Collisions

    Soejima K., Okuno K., Kaneko Y.

    44 ( 4 )   16 - 16   1989.3

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Awards

  • JSR Award for Young Scientist

    2000  

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  • 日本放射光学会 若手奨励賞

    2000  

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Research Projects

  • Highly time resolved observation of creation for initial optical isomer excess with ultra sensitive optical purity measurements

    Grant number:22H01281

    2022.4 - 2025.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\14430000 ( Direct Cost: \11100000 、 Indirect Cost:\3330000 )

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  • Entangle states for photoelectrons from molecules have time and position dependence or not

    Grant number:18K03488

    2018.4 - 2021.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Soejima Koichi

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    Grant amount:\3510000 ( Direct Cost: \2700000 、 Indirect Cost:\810000 )

    Development of an apparatus for angular distribution measurements of photoelectrons or/and Auger electrons from triatomic molecules will soon be finished. We have selected that the method of the measurements is combination of a pulse selector for X ray and electron TOF with 2D detector. The detection efficiency of the method we selected is much higher than that of a conventional method for angular distribution measurement. A preliminary measurement for angular distribution of photoelectrons has been done in single photoionization of helium. The results is good enough for progressing the study of entangle states using interference pattern on angular correlation.

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  • Isotope effect with rotational coupling on charge exchange cross sections

    Grant number:26400529

    2014.4 - 2017.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Soejima Koichi, SAKAUE Hiroyuki, SHIMAKURA Noriyuki, HAYAKAWA Ryo, SATO Syunsuke

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

    We try to measure absolute cross sections of charge exchange processes for tungsten multiply charged ions with hydrogen, deuterium and helium atoms, which data are useful for a simulation revealed transfer processes into main plasma of heavy elements. In addition, we have developed an apparatus to measure relative cross sections for hydrogen and deuterium atom targets. We have plan to observe an isotope effect on charge exchange processes using the apparatus.

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  • Study of electron correlation for photo doubleionization processes with circularly polarized lights

    Grant number:13640399

    2001 - 2002

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    SOEJIMA Kouichi, YAGISHITA Akira, DANJO Atunori

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    Grant amount:\3700000 ( Direct Cost: \3700000 )

    A new experimental apparatus for studying photo doubleionization (PDI) process was developed. The apparatus have good energy and angular resolutions. The new apparatus was installed at BL-28A of Photon Factory in KEK. And angular correlation between photoelectrons from Ne was measured. The TDCS have four lobes. The TDCS become complex compare with the TDCS of helium with two lobes. This complexity of TDCS is responsible for the electron correlation. The TDCS was also different for different final states of photoelectron system. The detailed analysis was tried using the method for helium. Unfortunately, the correlation factor for photo doubleionization of neon could not obtained with the method. The new method for analysis of electron correlation have to be developed as soon as possible.
    "Dynamical node" on circular dichroism (CD) was also measured using the new apparatus. One can distribute the node on CD into two classes. One is the "geometrical node", which is responsible for the geometrical factor of detector position, photon polarization, etc. The other is the "dynamical node", which is responsible for the dynamical factor of reaction. The CD can be expressed as function of the complex amplitudes, phase difference between them, which describe the dynamical effects in PDI, and mutual angle between photoelectrons corresponding to geometrical factor. The geometrical factor implies that the CD vanishes at mutual angle of 0° and 180° (geometrical nodes). And the CD have also "dynamical nodes" related to the complex amplitudes. The CD vanishes at the same kinetic energy of photoelectrons, which correspond to the zero of complex amplitude, and even at different kinetic energy of photoelectrons, which correspond to the phase difference between complex amplitudes of 180°. The "Dynamical node", corresponding to the phase difference of 180°, was clearly observed on CD.

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  • 円偏光軟X線による二重光電離過程における電子相関の研究

    Grant number:12640388

    2000

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    副島 浩一

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    Grant amount:\2700000 ( Direct Cost: \2700000 )

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  • Dissociation of Molecules in Slow Collisions of Highly Charged Ions with Molecules

    Grant number:11640389

    1999 - 2000

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    DANJO Atsunori, YOSHINO Masuhiro, SOEJIMA Kouichi

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    Grant amount:\3400000 ( Direct Cost: \3400000 )

    Single and multiple electron capture processes are studied in slow collisions between Ar^<q+> (q=6-9) ions and N_2 and CO molecules. The contribution of dissociative and non-dissociative channels are determined as well as the kinetic energies of the fragments of the molecular ions.
    We present experimental results of multiple electron capture processes in 1.75q keV Ar^<q+> (q=6-9) collisions with N_2 and CO molecules. The charge state of the scattered ions Ar^<(q-1)+> (j=1,2,3) are analyzed in coincidence with the recoil molecular ions extracted from the collision region by an electric field (10V/cn - 50V/cm) and analyzed by a time-of-flight method (TOF).
    In the present TOF spectrometer, the ions with kinetic energies greater than a certain value, which depends on the extraction field, can not reach the detector. This causes a splitting of the TOF spectrum into one 'forward' and the other 'backward' peak.

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  • Differential cross sections for the electron impact excitation of OィイD23ィエD2

    Grant number:10640381

    1998 - 1999

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    TAKAHASI Toshiyasu, SOEJIMA Kouichi, DANJO Atsunori, KIYAMA Yoshitaka

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

    In electron-molecule collisions, one of the important process is vibrational excitation. The study of electron-impact vibrational excitation of molecules is needed in various field such as gas lasers, radiation physics and environmental science in the atmosphere.
    Elastic and inelastic scattering of electrons from 0ィイD23ィエD2 and COィイD22ィエD2 molecules have been studied by cross beam method. Energy loss spectra have been measured at scattering angles from 20° to 120° in an incident electron energy range from 2 eV to 10 eV. Because of a rather poor energy resolution of the present spectrometer and the close spacing in energy of the vibrational modes, it is difficult to resolve their individual contributions. Hence a least squares fitting procedure has been employed to unfold the intensity of the individual modes, where the energy of the vibrational modes was taken from the known spectroscopic constants.
    The elastic differential cross sections (DCS) are placed on an absolute scale by normalizing to the absolute DCS for He with a relative flow technique. The inelastic cross sections are normalized to the elastic cross sections by using the measured inelastic to elastic intensity ratios. The elastic cross section for 0ィイD23ィエD2 and COィイD22ィエD2, and the (010), (100), (001) and (020) vibrational excitation cross sections have been compared with the previous experimental and theoretical results.

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  • 二重光電離過程の円二色性観測による電子相関の研究

    Grant number:09740330

    1997 - 1998

    System name:科学研究費助成事業

    Research category:奨励研究(A)

    Awarding organization:日本学術振興会

    副島 浩一

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    現在までに,電子相関の効果を解明するため二重光電離過程で生じる電子間の角度相関を以下の条件で測定した。実験は高エネルギー加速器研究機構・物質科学研究所・放射光施設内の円偏光ビームラインBL-28Aでおこなった。
    (1) Heを標的とし光のエネルギーから電子の結合エネルギーを差し引いた余剰エネルギーが
    (I) 10eVで放出電子が余剰エネルギーを1:1,1:2,1:8に分け合う場合。
    (II) 40eVで放出電子が余剰エネルギーを1:1,1:7,1:19に分け合う場合。
    (2) Neを標的とし終状態がHeの場合と同じ^1Poについて余剰エネルギーが40eVで放出電子が余剰エネルギーを1:1,1:2,1:8に分け合う場合。
    (1),(2)のいずれの場合も,右回り円偏光と左回り円偏光による測定結果の差,円二色性が観測された(余剰エネルギー等配分の場合は除く)。(1)-(I)については観測データの解析も終了し,これまで報告されていないアンバランスに余剰エネルギーが分配される場合の双極子遷移モーメントの導出に成功した。この双極子遷移モーメントを使って円および直線偏光成分が電子の角度相関に与える寄与を見積もったところ,放射光に含まれる割合が円偏光に比べて低い直線偏光成分の寄与が予想よりはるかに大きいことがわかった。そこで測定データからこの直線偏光成分の影響を取り去り,真の円二色性を引き出すことを試み,それに成功した。(1)-(II)および(2)については現在解析をおこなっている最中である。
    本研究で得られた結果は世界的に注目され,オーストラリアのオーストラリア国際大学Dr.Kheifetsから彼がおこなった理論計算と本結果を比較するためデータの提供を求められた,また,イギリスのニューカッスル大学Dr.Reddishとの共同研究が開始される予定である。

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  • 希ガス原子の二重光電離過程における電子相関の研究

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    Grant type:Competitive

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  • 多価イオンの電子捕獲過程に関する研究

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    Grant type:Competitive

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  • Electron correlation study in double photoionization of rare gas atoms

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    Grant type:Competitive

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  • Study on charge transter process of highly charged ions

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    Grant type:Competitive

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Teaching Experience

  • 自然環境科学研究演習

    2023
    Institution name:新潟大学

  • 量子化学

    2023
    Institution name:新潟大学

  • 理学基礎演習

    2022
    Institution name:新潟大学

  • 海外研修

    2022
    Institution name:新潟大学

  • 課題研究(自然環境)C

    2022
    Institution name:新潟大学

  • 課題研究(自然環境)B

    2022
    Institution name:新潟大学

  • 海外英語研修

    2022
    Institution name:新潟大学

  • 自然環境科学特論A

    2022
    Institution name:新潟大学

  • 化学反応論

    2021
    Institution name:新潟大学

  • 環境物理学特論II

    2021
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2021
    Institution name:新潟大学

  • 課題研究C

    2021
    Institution name:新潟大学

  • 課題研究B

    2021
    Institution name:新潟大学

  • 自然環境科学

    2021
    Institution name:新潟大学

  • 課題研究(自然環境)A

    2020
    Institution name:新潟大学

  • 課題研究(自然環境)B

    2020
    -
    2022
    Institution name:新潟大学

  • 課題研究(自然環境)C

    2020
    -
    2022
    Institution name:新潟大学

  • 課題研究

    2020
    -
    2021
    Institution name:新潟大学

  • 科学史

    2018
    Institution name:新潟大学

  • 自然環境科学総論

    2018
    Institution name:新潟大学

  • 自然環境科学実験C1

    2017
    Institution name:新潟大学

  • 物理学基礎BⅠ

    2017
    Institution name:新潟大学

  • 自然環境科学実験C2

    2017
    Institution name:新潟大学

  • 数理演習

    2017
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  • 課題研究B

    2017
    -
    2021
    Institution name:新潟大学

  • 課題研究C

    2017
    -
    2021
    Institution name:新潟大学

  • 物質科学A

    2017
    -
    2021
    Institution name:新潟大学

  • 課題研究A

    2017
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    2021
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2017
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    2019
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  • 専門力アクティブ・ラーニング

    2017
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    2019
    Institution name:新潟大学

  • 環境物理学特論Ⅰ

    2017
    -
    2019
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  • 環境経済システム論I

    2017
    Institution name:新潟大学

  • 安全教育

    2016
    -
    2017
    Institution name:新潟大学

  • 地球システム科学

    2016
    Institution name:新潟大学

  • 自然科学総論Ⅴ

    2015
    Institution name:新潟大学

  • 課題研究(自然環境)

    2015
    Institution name:新潟大学

  • 自然科学実験法

    2014
    -
    2017
    Institution name:新潟大学

  • エネルギー物質科学

    2013
    Institution name:新潟大学

  • 物理学基礎A I

    2013
    -
    2016
    Institution name:新潟大学

  • 研究発表演習Ⅰ(学外発表)

    2013
    -
    2015
    Institution name:新潟大学

  • 環境科学特定演習Ⅰ

    2013
    -
    2015
    Institution name:新潟大学

  • 自然環境科学特論A

    2012
    -
    2022
    Institution name:新潟大学

  • 研究発表演習Ⅰ(中間発表)

    2012
    -
    2015
    Institution name:新潟大学

  • 環境科学特定研究Ⅰ

    2012
    -
    2015
    Institution name:新潟大学

  • 環境科学セミナーⅠ

    2012
    -
    2015
    Institution name:新潟大学

  • 環境科学総合演習Ⅰ

    2012
    -
    2015
    Institution name:新潟大学

  • 高層大気科学

    2011
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    2022
    Institution name:新潟大学

  • 環境物理学特論Ⅲ

    2011
    -
    2014
    Institution name:新潟大学

  • 基礎量子力学

    2010
    -
    2022
    Institution name:新潟大学

  • 基礎数理演習II

    2010
    -
    2016
    Institution name:新潟大学

  • 基礎数理演習I

    2009
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    2016
    Institution name:新潟大学

  • 原子分子論

    2009
    -
    2014
    Institution name:新潟大学

  • 環境学入門

    2009
    -
    2011
    Institution name:新潟大学

  • 原子分子科学

    2009
    -
    2011
    Institution name:新潟大学

  • 環境物理学特論Ⅱ

    2008
    -
    2018
    Institution name:新潟大学

  • 原子分子物理学II

    2007
    -
    2021
    Institution name:新潟大学

  • 基礎物理学実験

    2007
    -
    2017
    Institution name:新潟大学

  • 自然環境科学実験C

    2007
    -
    2016
    Institution name:新潟大学

  • 環境科学スタディスキルズ

    2007
    -
    2016
    Institution name:新潟大学

  • 自然環境科学概論C

    2007
    -
    2016
    Institution name:新潟大学

  • 物理学基礎実験

    2007
    -
    2015
    Institution name:新潟大学

  • 基礎電気磁気学演習

    2007
    -
    2009
    Institution name:新潟大学

  • 環境物理学特論II

    2007
    Institution name:新潟大学

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