Updated on 2025/06/27

写真b

 
KUMA,SUSUMU
 
*Items subject to periodic update by Rikkyo University (The rest are reprinted from information registered on researchmap.)
Affiliation*
College of Science Department of Physics
Graduate School of Science Doctoral Program in Physics
Graduate School of Science Master's Program in Physics
Title*
Associate Professor
Campus Career*
  • 4 2025 - Present 
    College of Science   Department of Physics   Associate Professor
  • 4 2025 - Present 
    Graduate School of Science   Master's Program in Physics   Associate Professor
  • 4 2025 - Present 
    Graduate School of Science   Doctoral Program in Physics   Associate Professor
 

Papers

  • Laser spectroscopy of the QED-sensitive transition in Ar 14 +

    Yoshiki Miya, Naoki Kimura, Daiki Ito, Priti, Masaaki Baba, Susumu Kuma, Toshiyuki Azuma, Nobuyuki Nakamura

    New Journal of Physics   1 6 2025

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1367-2630/ade467

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  • Fermi resonance in the radiative vibrational cooling dynamics of N2O+

    S. Harayama, S. Kuma, N. Kimura, K. C. Chartkunchand, M. Baba, T. Murakami, T. Takayanagi, K. Yagi, T. Yamaguchi, Y. Nakano, T. Azuma

    Physical Review A   5 3 2025

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.111.032803

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  • Infrared Spectroscopy of Radical Cation Clusters (NH3)2+ and (NH3)3+

    Amandeep Singh, Arisa Iguchi, Tom C. Bernaards, Zane Golpariani, Kenta Mizuse, Asuka Fujii, Hajime Tanuma, Toshiyuki Azuma, Susumu Kuma, Andrey Vilesov

    The Journal of Physical Chemistry A   26 2 2025

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1021/acs.jpca.4c08362

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  • Exploring Molecular Superfluidity in Hydrogen Clusters

    Pavle Djuricanin, Takamasa Momose, Hatsuki Otani, Susumu Kuma, Shinichi Miura, Majd Mustafa, Jeff C. W. Lee

    Science Advances   21 2 2025

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1126/sciadv.adu1093

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  • Radiative stabilization of C2− against electron detachment

    S. Iida, S. Kuma, S. Masuda, H. Tanuma, M. Baba, H. Shiromaru, T. Azuma

    Physical Review A   24 10 2024

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.110.043117

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  • Size distribution of helium droplets in the condensation regime of a pulsed beam

    A. Iguchi, A. Hirota, S. Menk, T. Yamaguchi, H. Tanuma, J. R. Harries, S. Kuma, T. Azuma

    Low Temperature Physics   1 9 2024

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/10.0028187

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  • High-resolution electronic spectroscopy of buffer-gas-cooled metal-phthalocyanines

    Yuki Miyamoto, Masaaki Baba, Katsunari Enomoto, Ayami Hiramoto, Kana Iwakuni, Susumu Kuma

    Low Temperature Physics50 ( 9 ) 808 - 812   1 9 2024

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

    High-resolution absorption spectra of the S1←S0000 transition of buffer-gas-cooled magnesium-phthalocyanine, zinc-phthalocyanine, and chloroaluminum-phthalocyanine are presented. The low temperature achieved through buffer gas cooling allowed the observation of a partially resolved rotational structure in each spectrum. We compare these structures with the previously observed high-resolution spectrum of free-base phthalocyanine. Despite the similar molecular structures of these molecules, the spectral characteristics of the rotational envelope vary depending on the individual molecular structures.

    DOI: 10.1063/10.0028188

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  • Laboratory Transition-rate Measurement of the Coronal Intercombination Line of Ar xv by Time-resolved Laser Spectroscopy Peer-reviewed

    Naoki Kimura, Yoshiki Miya, Daiki Ito, Priti, Daiji Kato, Masaaki Baba, Susumu Kuma, Toshiyuki Azuma, Nobuyuki Nakamura

    The Astrophysical Journal972   12   1 9 2024

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

    DOI: 10.3847/1538-4357/ad643e

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  • Analysis on high-resolution spectrum of the S1–S0 transition of free-base phthalocyanine

    Yuki Miyamoto, Ayami Hiramoto, Kana Iwakuni, Susumu Kuma, Katsunari Enomoto, Naofumi Nakayama, Masaaki Baba

    The Journal of Chemical Physics   14 4 2024

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0191810

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  • Newly observed low-lying Ω = 1 state of PbO

    Katsunari Enomoto, Taichi Tojo, Kaori Kobayashi, Susumu Kuma, Ayami Hiramoto, Yuki Miyamoto, Masaaki Baba

    The Journal of Chemical Physics   7 4 2024

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0196184

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  • Vibrational spectroscopy of aniline cations and their H-loss cations in helium droplets

    Arisa Iguchi, Amandeep Singh, Susumu Kuma, Hajime Tanuma, Toshiyuki Azuma

    Journal of Molecular Spectroscopy   3 2024

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jms.2024.111903

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  • Direct measurement of delayed-detachment rate constants of C7−

    S. Iida, S. Kuma, J. W. Niman, S. Masuda, H. Tanuma, P. Ferrari, K. Hansen, H. Shiromaru, T. Azuma

    Physical Review A   11 12 2023

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.108.062808

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  • Hyperfine-structure-resolved laser spectroscopy of many-electron highly charged ions

    Naoki Kimura, Priti, Yasutaka Kono, Pativate Pipatpakorn, Keigo Soutome, Naoki Numadate, Susumu Kuma, Toshiyuki Azuma, Nobuyuki Nakamura

    Communications Physics6 ( 1 )   12 2023

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s42005-023-01127-x

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  • Isolation and Infrared Spectroscopic Characterization of Hemibonded Water Dimer Cation in Superfluid Helium Nanodroplets

    Arisa Iguchi, Amandeep Singh, Stefan Bergmeister, Andrew A. Azhagesan, Kenta Mizuse, Asuka Fujii, Hajime Tanuma, Toshiyuki Azuma, Paul Scheier, Susumu Kuma, Andrey F. Vilesov

    The Journal of Physical Chemistry Letters   14 9 2023

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1021/acs.jpclett.3c02150

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  • Doppler-free Spectroscopy of Buffer-Gas-Cooled Calcium Monohydroxide. International journal

    Yuki Miyamoto, Reo Tobaru, Yuiki Takahashi, Ayami Hiramoto, Kana Iwakuni, Susumu Kuma, Katsunari Enomoto, Masaaki Baba

    The journal of physical chemistry. A127 ( 21 ) 4758 - 4763   1 6 2023

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

    In this study, we report the Doppler-free spectra of buffer-gas-cooled CaOH. We observed five Doppler-free spectra containing low-J Q1 and R12 transitions, which were only partially resolved by previous Doppler-limited spectroscopies. The spectra frequencies were corrected using the Doppler-free spectra of iodine molecules; accordingly, the uncertainty was estimated to be below 10 MHz. We determined the spin-rotation constant in the ground state, which agrees with the values reported in the literature obtained based on millimeter-wave data within 1 MHz. This suggests that the relative uncertainty is much smaller. The present study demonstrates the Doppler-free spectroscopy of a polyatomic radical and the broad applicability of the buffer gas cooling method to molecular spectroscopy. CaOH is the only polyatomic molecule that can be directly laser-cooled and trapped in a magneto-optical trap. High-resolution spectroscopy of such molecules is useful for establishing efficient laser cooling schemes of polyatomic molecules.

    DOI: 10.1021/acs.jpca.2c08565

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  • Measurement of Doppler effects in a cryogenic buffer-gas cell

    Ayami Hiramoto, Masaaki Baba, Katsunari Enomoto, Kana Iwakuni, Susumu Kuma, Yuiki Takahashi, Reo Tobaru, Yuki Miyamoto

    Physical Review A   13 4 2023

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.107.043114

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  • Electric-quadrupole transition-rate measurement of a highly charged ion in an electron-beam ion trap using pulsed laser excitation from a metastable state

    Naoki Kimura, Priti, Susumu Kuma, Toshiyuki Azuma, Nobuyuki Nakamura

    Physical Review A   9 2 2023

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.107.022805

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  • High-resolution spectroscopy of buffer-gas-cooled phthalocyanine. International journal

    Yuki Miyamoto, Reo Tobaru, Yuiki Takahashi, Ayami Hiramoto, Kana Iwakuni, Susumu Kuma, Katsunari Enomoto, Masaaki Baba

    Communications chemistry5 ( 1 ) 161 - 161   29 11 2022

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    For over five decades, studies in the field of chemical physics and physical chemistry have primarily aimed to understand the quantum properties of molecules. However, high-resolution rovibronic spectroscopy has been limited to relatively small and simple systems because translationally and rotationally cold samples have not been prepared in sufficiently large quantities for large and complex systems. In this study, we present high-resolution rovibronic spectroscopy results for large gas-phase molecules, namely, free-base phthalocya-nine (FBPc). The findings suggest that buffer-gas cooling may be effective for large molecules introduced via laser ablation. High-resolution electronic spectroscopy, combined with other experimental and theoretical studies, will be useful in understanding the quantum properties of molecules. These findings also serve as a guide for quantum chemical calculations of large molecules.

    DOI: 10.1038/s42004-022-00783-4

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  • Low-J Transitions in A˜2Π(0,0,0)−X˜2Σ+(0,0,0) Band of Buffer-gas-cooled CaOH

    Yuiki Takahashi, Masaaki Baba, Katsunari Enomoto, Ayami Hiramoto, Kana Iwakuni, Susumu Kuma, Reo Tobaru, Yuki Miyamoto

    The Astrophysical Journal   1 9 2022

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.3847/1538-4357/ac87fb

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  • Photodetachment Spectroscopy of Highly Excited \(\text{C}_{2}^{ - }\) and Their Temporal Evolution in the Ion Storage Ring RICE

    Masatomi Iizawa, Susumu Kuma, Naoki Kimura, Kiattichart Chartkunchand, Sakumi Harayama, Toshiyuki Azuma, Yuji Nakano

    Journal of the Physical Society of Japan   15 8 2022

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.7566/JPSJ.91.084302

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  • IR-photon quenching of delayed electron detachment from hot pentacene anions

    S. Iida, S. Kuma, M. Kuriyama, T. Furukawa, M. Kusunoki, H. Tanuma, K. Hansen, H. Shiromaru, T. Azuma

    Physical Review A   27 10 2021

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.104.043114

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  • Correction to "State-Selective Observation of Radiative Cooling of Vibrationally Excited C2-". International journal

    Shimpei Iida, Susumu Kuma, Hajime Tanuma, Toshiyuki Azuma, Haruo Shiromaru

    The journal of physical chemistry letters12 ( 37 ) 8980 - 8981   23 9 2021

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  • Electronic spectroscopy of Mg-phthalocyanine embedded in cold hydrogen clusters produced by a pulsed nozzle

    Hatsuki Otani, Hiroko Nakahara, Haruka Goto, Susumu Kuma, Takamasa Momose

    The Journal of Chemical Physics   28 7 2021

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0056499

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  • Status of the Laser Spectroscopy and Merged-beam Experiments at RICE Peer-reviewed

    Y. Nakano, R. Igosawa, S. Iida, S. Okada, M. Lindley, S. Menk, R. Nagaoka, T. Hashimoto, S. Yamada, T. Yamaguchi, S. Kuma, T. Azuma

    Proceedings of 10th International Conference on Nuclear Physics at Storage Rings (STORI’17)   15 6 2021

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    Publishing type:Research paper (international conference proceedings)   Publisher:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.35.011006

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  • State-Selective Observation of Radiative Cooling of Vibrationally Excited C2. International journal

    Shimpei Iida, Susumu Kuma, Hajime Tanuma, Toshiyuki Azuma, Haruo Shiromaru

    The journal of physical chemistry letters11 ( 24 ) 10526 - 10531   17 12 2020

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

    We have observed radiative cooling of vibrationally excited C2- in the X2Σg+ electronic ground state via electronic transitions to near-degenerate low-lying vibrational levels of the A2Πu electronic excited state. Combining an ion storage technique with high-resolution detachment spectroscopy, we were able to assign rovibronic transitions to the resulting complex spectra. The time evolution of the population at specific vibrational states was measured up to 60 ms, providing the first quantitative experimental support for the long-standing theoretical predictions.

    DOI: 10.1021/acs.jpclett.0c03196

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  • Photodissociation spectroscopy of N2O+ in the ion storage ring RICE

    R. Igosawa, A. Hirota, N. Kimura, S. Kuma, K. C. Chartkunchand, P. M. Mishra, M. Lindley, T. Yamaguchi, Y. Nakano, T. Azuma

    The Journal of Chemical Physics153 ( 18 ) 184305 - 184305   14 11 2020

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

    DOI: 10.1063/5.0027805

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  • Threshold Photodetachment Spectroscopy of the Positronium Negative Ion. International journal

    Koji Michishio, Susumu Kuma, Yugo Nagata, Luca Chiari, Taro Iizuka, Riki Mikami, Toshiyuki Azuma, Yasuyuki Nagashima

    Physical review letters125 ( 6 ) 063001 - 063001   7 8 2020

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

    Threshold photodetachment spectroscopy of the positronium negative ion has been accomplished for the first time employing an efficient source of the ions and photodetachment techniques combined with a tunable optical parametric oscillator and amplifier laser. The photodetachment threshold, corresponding to the electron affinity of positronium (1^{3}S_{1}), was determined to be 326.88±0.09(stat)±0.10(syst)  meV by laser photodetachment threshold measurements. This result is consistent with a variational calculation corrected for leading relativistic and quantum electrodynamical effects.

    DOI: 10.1103/PhysRevLett.125.063001

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  • Radiative cooling dynamics of isolated N2 O+ ions in a cryogenic electrostatic ion storage ring

    A. Hirota, R. Igosawa, N. Kimura, S. Kuma, K. C. Chartkunchand, P. M. Mishra, M. Lindley, T. Yamaguchi, Y. Nakano, T. Azuma

    Physical Review A102 ( 2 )   8 2020

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.102.023119

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  • Rotationally Resolved Excitation Spectra Measured by Slow Electron Detachment from Si2. International journal

    Shimpei Iida, Susumu Kuma, Jun Matsumoto, Takeshi Furukawa, Hajime Tanuma, Toshiyuki Azuma, Haruo Shiromaru, Vitali Zhaunerchyk, Klavs Hansen

    The journal of physical chemistry letters11 ( 13 ) 5199 - 5203   2 7 2020

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

    Laser-induced delayed electron detachment from Si2- stored in an electrostatic ion storage ring was observed on the 10 microsecond time scale. The excitation spectra for photon energies near threshold show well-resolved multipeak structures, which are attributed to rovibronic transitions to the electronic excited state. This structure appears only in the signal measured with the delay. The occurrence of delayed detachment on such a long time scale is unusual for diatomic molecules, suggesting that both the autodetachment and fluorescence are slow.

    DOI: 10.1021/acs.jpclett.0c01057

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  • Photodetachment of negative ion beams for the ion-neutral merged-beam experiments at RICE

    M. Iizawa, S. Iida, S. Kuma, T. Azuma, Y. Nakano

    Journal of Physics: Conference Series1412 ( 12 )   11 6 2020

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    Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1088/1742-6596/1412/12/122006

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  • Vibrational and rotational cooling dynamics of the triatomic molecular ion N<inf>2</inf>O<sup>+</sup>stored in RICE

    R. Igosawa, R. Igosawa, A. Hirota, A. Hirota, T. Yamaguchi, M. Lindley, K. Chartkunchand, Y. Nakano, S. Kuma, T. Azuma, T. Azuma

    Journal of Physics: Conference Series1412 ( 23 )   11 6 2020

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    Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1088/1742-6596/1412/23/232002

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  • Production of cold molecular ions in superfluid helium droplets

    A. Iguchi, A. Iguchi, H. Otani, H. Otani, S. Kuma, H. Tanuma, T. Azuma, T. Azuma

    Journal of Physics: Conference Series1412 ( 23 )   11 6 2020

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    Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1088/1742-6596/1412/23/232010

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  • Towards investigations of pre-cooled ions stored in the RICE storage ring via action spectroscopy

    K. C. Chartkunchand, S. Menk, A. Hirota, A. Hirota, R. Igosawa, R. Igosawa, S. Kuma, Y. Nakano, Y. Nakano, T. Azuma, T. Azuma

    Journal of Physics: Conference Series1412 ( 23 )   11 6 2020

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    Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1088/1742-6596/1412/23/232003

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  • Superfluorescence, Free-Induction Decay, and Four-Wave Mixing: Propagation of Free-Electron Laser Pulses through a Dense Sample of Helium Ions. International journal

    James R Harries, Hiroshi Iwayama, Susumu Kuma, Masatomi Iizawa, Norihiro Suzuki, Yoshiro Azuma, Ichiro Inoue, Shigeki Owada, Tadashi Togashi, Kensuke Tono, Makina Yabashi, Eiji Shigemasa

    Physical review letters121 ( 26 ) 263201 - 263201   28 12 2018

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    We report an experimental and numerical study of the propagation of free-electron laser pulses (wavelength 24.3 nm) through helium gas. Ionization and excitation populates the He^{+} 4p state. Strong, directional emission was observed at wavelengths of 469, 164, 30.4, and 25.6 nm. We interpret the emissions at 469 and 164 nm as 4p-3s-2p cascade superfluorescence, that at 30.4 nm as yoked superfluorescence on the 2p-1s transition, and that at 25.6 nm as free-induction decay of the 3p state.

    DOI: 10.1103/PhysRevLett.121.263201

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  • Superfluorescence/Superradiance in Helium Following Free-Electron Laser Excitation

    J. R. Harries, S. Kuma, H. Iwayama, E. Shigemasa

    Springer Proceedings in Physics202   105 - 108   2018

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    Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1007/978-3-319-73025-7_16

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  • Pulsed beam of extremely large helium droplets

    Susumu Kuma, Toshiyuki Azuma

    Cryogenics88   78 - 80   12 2017

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.cryogenics.2017.10.016

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  • Study of superconducting transition-edge-sensor microcalorimeters for detecting molecules

    Okada S., Ichinohe Y., Ishisaki Y., Kuma S., Nakano T., Nakano Y., Noda H., O'Neil G. C., Reintsema C. D., Schmidt D. R., Swetz D. S., Azuma T., Tatsuno H., Ueda S., Ullom J. N., Yamada S., Bennett D. A., Doriese W. B., Fowler J. W., Hashimoto T., Hayakawa R., Hays-Wehle J., Hilton G.

    Meeting Abstracts of the Physical Society of Japan72 ( 0 ) 495 - 495   2017

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    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.72.2.0_495

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  • Study of atomic and molecular collisions using superconducting transition-edge-sensor microcalorimeters

    Okada S., Azuma T., Kuma S., Nakano Y., Yamada S.

    Meeting Abstracts of the Physical Society of Japan72 ( 0 ) 673 - 673   2017

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    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.72.1.0_673

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  • Single-atom response of helium atoms to pulses from an EUV free-electron laser: Implications for the subsequent development of superfluorescence

    James R. Harries, Chiaki Ohae, Susumu Kuma, Kyo Nakajima, Tadashi Togashi, Yuki Miyamoto, Noboru Sasao, Hiroshi Iwayama, Mitsuru Nagasono, Makina Yabashi, Eiji Shigemasa

    Physical Review A94 ( 6 )   22 12 2016

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.94.063416

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  • Ro-vibrational Spectra of (para-H2 )N -CH4 in He Droplets. International journal

    Hiromichi Hoshina, Russell Sliter, Aakash Ravi, Susumu Kuma, Takamasa Momose, Andrey F Vilesov

    Chemphyschem : a European journal of chemical physics and physical chemistry17 ( 22 ) 3818 - 3825   18 11 2016

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

    In this work, we report on the infrared spectroscopic study of clusters of CH4 molecules with up to N=80 para-hydrogen molecules assembled inside He droplets. Upon increase of the number of the added para-hydrogen molecules up to about N=12, both the rotational constant, B, and the origin frequency of the υ3 band of CH4 decrease gradually. In the range of 6 ≤N≤12, the spectra indicate some abrupt changes of B and υ3 with both values being approximately constant at N≥12. The origin of this effect is discussed. Comparison of the spectra of methane molecules in para-hydrogen clusters to that in solid para-hydrogen is also presented.

    DOI: 10.1002/cphc.201600484

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  • Observation of a shape resonance of the positronium negative ion. International journal

    Koji Michishio, Tsuneto Kanai, Susumu Kuma, Toshiyuki Azuma, Ken Wada, Izumi Mochizuki, Toshio Hyodo, Akira Yagishita, Yasuyuki Nagashima

    Nature communications7   11060 - 11060   17 3 2016

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    When an electron binds to its anti-matter counterpart, the positron, it forms the exotic atom positronium (Ps). Ps can further bind to another electron to form the positronium negative ion, Ps(-) (e(-)e(+)e(-)). Since its constituents are solely point-like particles with the same mass, this system provides an excellent testing ground for the three-body problem in quantum mechanics. While theoretical works on its energy level and dynamics have been performed extensively, experimental investigations of its characteristics have been hampered by the weak ion yield and short annihilation lifetime. Here we report on the laser spectroscopy study of Ps(-), using a source of efficiently produced ions, generated from the bombardment of slow positrons onto a Na-coated W surface. A strong shape resonance of (1)P(o) symmetry has been observed near the Ps (n=2) formation threshold. The resonance energy and width measured are in good agreement with the result of three-body calculations.

    DOI: 10.1038/ncomms11060

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  • Superfluorescence/superradiance emitted following excitation of helium atoms with EUV-FEL radiation resonant to 1s4p excitation: experiment and simulation

    Harries James R, Iwayama H, Kuma S, Miyamoto Y, Nagasono M, Ohae C, Togashi T, Nakajima K, Shigemasa E, Sasao N

    Meeting Abstracts of the Physical Society of Japan71   541 - 541   2016

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    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.71.2.0_541

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  • Simultaneous measurements of superradiance at multiple wavelength from helium excited states: II. Analysis

    Chiaki Ohae, James R. Harries, Hiroshi Iwayama, Kentarou Kawaguchi, Susumu Kuma, Yuki Miyamoto, Mitsuru Nagasono, Kyo Nakajima, Itsuo Nakano, Eiji Shigemasa, Noboru Sasao, Satoshi Uetake, Tomonari Wakabayashi, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    Journal of the Physical Society of Japan85 ( 3 )   2016

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.7566/JPSJ.85.034301

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  • Rate amplification of the two photon emission from para-hydrogen toward the neutrino mass measurement

    Takahiko Masuda, Hideaki Hara, Yuki Miyamoto, Susumu Kuma, Itsuo Nakano, Chiaki Ohae, Noboru Sasao, Minoru Tanaka, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    Hyperfine Interactions236 ( 1-3 ) 73 - 77   1 11 2015

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s10751-015-1177-1

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  • Observation of a resonance in the photodetachment of positronium negative ions

    Koji Michishio, Susumu Kuma, Tsuneto Kanai, Toshiyuki Azuma, Ken Wada, Izumi Mochizuki, Toshio Hyodo, Akira Yagishita, Yasuyuki Nagashima

    Journal of Physics: Conference Series635 ( 5 )   7 9 2015

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    Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1088/1742-6596/635/5/052050

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  • Erratum: A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses (Journal of Physics B: Atomic, Molecular and Optical Physics 48:105002(2015))

    James R. Harries, Hiroshi Iwayama, Mitsuru Nagasono, Tadashi Togashi, Makina Yabashi, Susumu Kuma, Kyo Nakajima, Yuki Miyamoto, Chiaki Ohae, Noboru Sasao, Eiji Shigemasa

    Journal of Physics B: Atomic, Molecular and Optical Physics48 ( 15 )   14 8 2015

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0953-4075/48/15/159601

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  • A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses Peer-reviewed

    Harries James R, Iwayama Hiroshi, Nagasono Mitsuru, Togashi Tadashi, Yabashi Makina, Kuma Susumu, Nakajima Kyo, Miyamoto Yuki, Ohae Chiaki, Sasao Noboru, Shigemasa Eiji

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS48 ( 10 )   28 5 2015

  • Infrared absorption spectra of SiF<inf>4</inf> and its clusters in solid parahydrogen

    Hiroki Ooe, Yuki Miyamoto, Susumu Kuma, Noboru Sasao, Kentarou Kawaguchi

    Chemical Physics Letters631-632   54 - 58   17 5 2015

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.cplett.2015.04.057

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  • Simultaneous measurements of super-radiance at multiple wavelengths from helium excited states: I. Experiment

    Kyo Nakajima, James R. Harries, Hiroshi Iwayama, Susumu Kuma, Yuki Miyamoto, Mitsuru Nagasono, Chiaki Ohae, Tadashi Togashi, Makina Yabashi, Eiji Shigemasa, Noboru Sasao

    Journal of the Physical Society of Japan84 ( 5 )   15 5 2015

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    DOI: 10.7566/JPSJ.84.054301

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  • Low-lying electronic states in bismuth trimer Bi₃ as revealed by laser-induced NIR emission spectroscopy in solid Ne. International journal

    Tomonari Wakabayashi, Yoriko Wada, Kyo Nakajima, Yusuke Morisawa, Susumu Kuma, Yuki Miyamoto, Noboru Sasao, Motohiko Yoshimura, Tohru Sato, Kentarou Kawaguchi

    The journal of physical chemistry. A119 ( 11 ) 2644 - 50   19 3 2015

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    DOI: 10.1021/jp509714f

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  • 24aBG-12 Superradiance in multi-level He atoms excited by EUV-FEL (II) Analysis

    Ohae Chiaki, HARRIES James R., Iwayama Hiroshi, Kuma Susumu, Miyamoto Yuki, Nggasono Mitsuru, Nakajima Kyo, Shigemasa Eiji, Wakabayashi Tomonari, Sasao Noboru

    Meeting Abstracts of the Physical Society of Japan70   772 - 772   2015

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

    DOI: 10.11316/jpsgaiyo.70.1.0_772

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  • 24aBG-11 Superradiance in multi-level He atoms excited by EUV-FEL (I) Experiment

    Nakajima K., HARRIES James R., Iwayama H., Kuma S., Miyamoto Y., Nggasono M., Ohae C., Togashi T., Shigemasa E., Sasao N.

    Meeting Abstracts of the Physical Society of Japan70   771 - 771   2015

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

    DOI: 10.11316/jpsgaiyo.70.1.0_771

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  • Production of ba metastable state via superradiance

    Chiaki Ohae, Atsushi Fukumi, Susumu Kuma, Yuki Miyamoto, Kyo Nakajima, Itsuo Nakano, Hajime Nanjo, Noboru Sasao, Satoshi Uetake, Tomonari Wakabayashi, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    Journal of the Physical Society of Japan83 ( 4 )   4 2014

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.7566/JPSJ.83.044301

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  • Iodine molecule for neutrino mass spectroscopy: Ab initio calculation of spectral rate

    Motomichi Tashiro, Masahiro Ehara, Susumu Kuma, Yuki Miyamoto, Noboru Sasao, Satoshi Uetake, Motohiko Yoshimura

    Progress of Theoretical and Experimental Physics2014 ( 1 )   1 2014

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/ptep/ptt118

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  • Observation of coherent two-photon emission from the first vibrationally excited state of hydrogen molecules

    Yuki Miyamoto, Hideaki Hara, Susumu Kuma, Takahiko Masuda, Itsuo Nakano, Chiaki Ohae, Noboru Sasao, Minoru Tanaka, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    Progress of Theoretical and Experimental Physics2014 ( 11 )   2014

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/ptep/ptu152

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  • 4.8 μm difference-frequency generation using a waveguide-PPLN crystal and its application to mid-infrared Lamb-dip spectroscopy. International journal

    Susumu Kuma, Yuki Miyamoto, Kousuke Tsutsumi, Noboru Sasao, Satoshi Uetake

    Optics letters38 ( 15 ) 2825 - 8   1 8 2013

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    DOI: 10.1364/OL.38.002825

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  • Diffusion of hydrogen fluoride in solid parahydrogen. International journal

    Hiroki Ooe, Yuki Miyamoto, Susumu Kuma, Kentarou Kawaguchi, Kyo Nakajima, Itsuo Nakano, Noboru Sasao, Jian Tang, Takashi Taniguchi, Motohiko Yoshimura

    The Journal of chemical physics138 ( 21 ) 214309 - 214309   7 6 2013

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

    DOI: 10.1063/1.4808035

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  • Observation of new near infrared emission band systems of small bismuth clusters in solid neon matrix

    Tomonari Wakabayashi, Makiko Tomioka, Yoriko Wada, Yuki Miyamoto, Jian Tang, Kentarou Kawaguchi, Susumu Kuma, Noboru Sasao, Hajime Nanjo, Satoshi Uetake, Motohiko Yoshimura, Itsuo Nakano

    European Physical Journal D67 ( 2 )   2 2013

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1140/epjd/e2012-30529-x

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  • Coherence decay measurement of v = 2 vibrons in solid parahydrogen. International journal

    Susumu Kuma, Yuki Miyamoto, Kyo Nakajima, Atsushi Fukumi, Kentarou Kawaguchi, Itsuo Nakano, Noboru Sasao, Minoru Tanaka, Jian Tang, Takashi Taniguchi, Satoshi Uetake, Tomonari Wakabayashi, Akihiro Yoshimi, Motohiko Yoshimura

    The Journal of chemical physics138 ( 2 ) 024507 - 024507   14 1 2013

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

    DOI: 10.1063/1.4773893

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  • Neutrino spectroscopy with atoms and molecules

    Atsushi Fukumi, Susumu Kuma, Yuki Miyamoto, Kyo Nakajima, Itsuo Nakano, Hajime Nanjo, Chiaki Ohae, Noboru Sasao, Minoru Tanaka, Takashi Taniguchi, Satoshi Uetake, Tomonari Wakabayashi, Takuya Yamaguchi, Akihiro Yoshimi, Motohiko Yoshimura

    Progress of Theoretical and Experimental Physics2012 ( 1 )   1 1 2012

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/ptep/pts066

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  • Spectroscopy of HF and HF-containing clusters in solid parahydrogen. International journal

    Yuki Miyamoto, Hiroki Ooe, Susumu Kuma, Kentarou Kawaguchi, Kyo Nakajima, Itsuo Nakano, Noboru Sasao, Jian Tang, Takashi Taniguchi, Motohiko Yoshimura

    The journal of physical chemistry. A115 ( 50 ) 14254 - 61   22 12 2011

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

    DOI: 10.1021/jp207419m

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  • ν<inf>4</inf> Band of CH<inf>4</inf> in helium nanodroplets: A probe of the dynamical response of a superfluid

    Aakash Ravi, Susumu Kuma, Christopher Yearwood, Birinder Kahlon, Majd Mustafa, Watheq Al-Basheer, Katsunari Enomoto, Takamasa Momose

    Physical Review A - Atomic, Molecular, and Optical Physics84 ( 2 )   26 8 2011

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevA.84.020502

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  • Laser induced fluorescence spectroscopy of tetracene with large Ar, Ne, and H2 clusters in superfluid He nanodroplets. International journal

    Susumu Kuma, Hiroko Nakahara, Masaaki Tsubouchi, Akira Takahashi, Majd Mustafa, Goeun Sim, Takamasa Momose, Andrey F Vilesov

    The journal of physical chemistry. A115 ( 25 ) 7392 - 9   30 6 2011

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

    DOI: 10.1021/jp203341r

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  • Infrared spectra and intensities of Ar-H(2)O and O(2)-H(2)O complexes in the range of the nu(3) band of H(2)O. International journal

    Susumu Kuma, Mikhail N Slipchenko, Takamasa Momose, Andrey F Vilesov

    The journal of physical chemistry. A114 ( 34 ) 9022 - 7   2 9 2010

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

    DOI: 10.1021/jp908450c

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  • Deceleration of molecules by dipole force potential: A numerical simulation

    Susumu Kuma, Takamasa Momose

    New Journal of Physics11   14 5 2009

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1367-2630/11/5/055023

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  • Laser induced fluorescence of Mg-phthalocyanine in He droplets: evidence for fluxionality of large H2 clusters at 0.38 K. International journal

    Susumu Kuma, Haruka Goto, Mikhail N Slipchenko, Andrey F Vilesov, Alexander Khramov, Takamasa Momose

    The Journal of chemical physics127 ( 21 ) 214301 - 214301   7 12 2007

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    DOI: 10.1063/1.2802303

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  • Study of complexes of water and ammonia molecules in He droplets

    Susumu Kuma, Mikhail N. Slipchenko, Takamasa Momose, Andrey F. Vilesov

    Chemical Physics Letters439 ( 4-6 ) 265 - 269   11 5 2007

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.cplett.2007.03.077

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  • Infrared spectra and intensities of the H2O and N2 complexes in the range of the nu1- and nu3-bands of water. International journal

    Susumu Kuma, Mikhail N Slipchenko, Kirill E Kuyanov, Takamasa Momose, Andrey F Vilesov

    The journal of physical chemistry. A110 ( 33 ) 10046 - 52   24 8 2006

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

    DOI: 10.1021/jp0624754

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  • Search for CCH<sup>-</sup>, NCO<sup>-</sup>, and NCS<sup>-</sup> negative ions in molecular clouds

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

    Publications of the Astronomical Society of Japan57 ( 2 ) 325 - 334   2005

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/pasj/57.2.325

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  • Fine structure of the (S(1)<--S(0)) band origins of phthalocyanine molecules in helium droplets. International journal

    Rudolf Lehnig, Mikhail Slipchenko, Susumu Kuma, Takamasa Momose, Boris Sartakov, Andrey Vilesov

    The Journal of chemical physics121 ( 19 ) 9396 - 405   15 11 2004

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

    DOI: 10.1063/1.1804945

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

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

    Optics letters28 ( 1 ) 37 - 9   1 1 2003

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    DOI: 10.1364/OL.28.000037

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  • Intense pulsed helium droplet beams

    Mikhail N. Slipchenko, Susumu Kuma, Takamasa Momose, Andrey F. Vilesov

    Review of Scientific Instruments73 ( 10 ) 3600   10 2002

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.1505661

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▼display all

Research Projects

  • レーザー誘起再帰蛍光法による未同定星間分子吸収線の起源分子探索

    日本学術振興会  科学研究費助成事業 

    古川 武, 谷口 琴美, 久間 晋, 斉藤 学

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    4 2024 - 3 2028

    Grant number:24H00252

    Grant amount:\49140000 ( Direct Cost: \37800000 、 Indirect Cost:\11340000 )

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  • Using soft X-ray coherent diffraction imaging to study and tailor the formation of superfluid helium droplets and quantum vortices within them

    日本学術振興会  科学研究費助成事業 

    HARRIES JAMES, 久間 晋

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    4 2023 - 3 2028

    Grant number:23H03670

    Grant amount:\18590000 ( Direct Cost: \14300000 、 Indirect Cost:\4290000 )

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  • Development of a cryogenic high precision molecular spectroscopy system for parity non-conservation measurements

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

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    4 2022 - 3 2026

    Grant number:22H01249

    Grant amount:\17810000 ( Direct Cost: \13700000 、 Indirect Cost:\4110000 )

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  • Exploring and controlling of extremely slow dynamics in isolated quantum few-body systems

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

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    4 2021 - 3 2026

    Grant number:21H04447

    Grant amount:\42770000 ( Direct Cost: \32900000 、 Indirect Cost:\9870000 )

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  • Cryogenic cooling of positronium atoms by ultrasonic cavitation

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

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    4 2022 - 3 2025

    Grant number:22H01240

    Grant amount:\17680000 ( Direct Cost: \13600000 、 Indirect Cost:\4080000 )

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  • Elucidation of selection rules in nano-optics and development of new energy conversion pathways

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

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    4 2021 - 3 2025

    Grant number:21H04644

    Grant amount:\43680000 ( Direct Cost: \33600000 、 Indirect Cost:\10080000 )

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  • 量子液滴ビームを駆使したナノ水素超流動相の微視的探索

    日本学術振興会  科学研究費助成事業 

    久間 晋, 三浦 伸一, 中野 祐司

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    4 2020 - 3 2024

    Grant number:20H04464

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

    本研究では、Ginzburgらにより予言された水素超流動相を実現するために、温度0.4Kのヘリウム液滴からなる量子液滴ビーム中にナノ水素凝縮体を生成し、微視的スケールでその量子物性に迫ることを目的とする。ナノ水素凝集体が示す液体性そして超流動性を、水素及び内包分子をプローブとするレーザー分光法を駆使し微視的なナノスケールから巨視スケールに近いミクロンサイズまでの幅広いサイズ領域で明らかにする。微視的スケールを超えて巨視的スケールでの超流動水素の実現可能性を見極めるための土台となる。
    本年度はまず、1) 低温パルスノズルから直接噴出した水素ガスにより生成される巨大水素クラスターの性質を、クラスタービーム速度測定と内包分子のスペクトル測定により明らかにした。特に、生成したクラスターはヘリウム液滴温度0.4Kまでは冷却されていないまでも、バルク凝固点13.8Kより遥かに低い5K以下の温度にあることが推察された。さらにこのクラスターが液体の性質を持つことをスペクトル測定により明らかにした。この結果を液滴サイズ10^5の巨大水素クラスターにおいて見出したことは、巨視的スケールでの物性との関連を調べる上で意義が大きい。2) 高強度ヘリウム液滴パルスビームを生成するためのパルスノズル及び液滴生成チャンバーを整備した。3) 量子モンテカルロ法に基づく水素分子の超流動シミュレーションを実施するためのプログラムコードのアップデートを実施した。
    これらの研究を、研究代表者を中心に2名の研究分担者と共に遂行した。

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  • Superfluorescence, free-induction decay, and four-wave mixing: experimental and numerical studies of the propagation of free-electron laser pulses through dense atomic/ionic media

    日本学術振興会  科学研究費助成事業 

    HARRIES JAMES, 久間 晋

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    4 2019 - 3 2023

    Grant number:19K12636

    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    本研究の目的は、自由電子レーザー由来の部分的コヒーレント「SASE」光の、高密度原子資料中の伝搬を観察し、その伝搬に伴って発生する超蛍光を始めとする量子光学現象の実現および制御である。そのためには自由電子レーザーSACLAを用いた実験および数値計算を行うのがプロジェクト全体を通しての目標である。短波長領域(164 nm、30.4 nm)発光を時分割に測定するための開発を行った。分光器と高速検出器を組み合わせて実験を計画し、2022年夏にSACLAのマシンタイムを確保できた。試料側では、気体の孤立した原子と比べてはるかに高い密度(つまりより短い原子間距離)を対象にするために、ヘリウム液滴を用いた実験も検討し、そのビーム発生装置の開発も始めた。これまでの成果については招待講演で発表した。

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  • Producing ultra-cold polyatomic molecules for observing the parity violation in chiral molecules

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    Miyamoto Yuki

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    4 2018 - 3 2022

    Grant number:18H01229

    Grant amount:\17160000 ( Direct Cost: \13200000 、 Indirect Cost:\3960000 )

    In this project, we performed buffer gas cooling and high-precision spectroscopy of the triatomic molecule CaOH. The temperature of CaOH in the buffer gas cell was evaluated, and the spectroscopic constants were determined with higher precision than before. Furthermore, we succeeded in observing the rotational structure of a larger molecule, phthalocyanine, by cooling it with buffer gas and performing high-resolution spectroscopy. This is an important achievement that shows that high-resolution spectroscopy is possible even for large molecules.

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  • Innovative approach to the study of atomic and molecular dynamics using superconducting molecular sensors

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    Okada Shinji

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    4 2018 - 3 2022

    Grant number:18H03714

    Grant amount:\44590000 ( Direct Cost: \34300000 、 Indirect Cost:\10290000 )

    We have established a new high-resolution mass spectrometry method for low-energy molecules using an array of superconducting transition-edge-sensor (TES) microcalorimeters as a superconducting "molecular" detector. The TES detector was successfully operated without thermal radiation windows in front of the superconducting sensors by introducing cylindrical thermal radiation shields and meshes cooled by a GM refrigerator. This enabled the world's first successful direct detection of neutral molecules and their mass measurement by a TES detector. Incorporating this system into a low-temperature electrostatic ion storage ring enables unparalleled atomic and molecular collision experiments. The merging collision experiments of stored ions and neutral molecules using the simultaneously developed neutral beam source are expected to make a great leap forward in the study of ion-molecule reactions in the low-temperature and dilute space environment.

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  • New approach to astrochemical reaction dynamics by a high-precision superconducting X-ray calorimeter

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

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    4 2019 - 3 2021

    Grant number:19H05195

    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

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  • Interdisciplinary science explored by cryogenic electrostatic storage ring: from astrochemistry to radiation biology

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    AZUMA TOSHIYUKI, MENK sebastian, OKADA shinji, YAMADA shinya

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    5 2014 - 3 2019

    Grant number:26220607

    Grant amount:\191100000 ( Direct Cost: \147000000 、 Indirect Cost:\44100000 )

    Using a cryogenic electrostatic ion storage ring device, it has become possible to accumulate atomic and molecular ions for a long period of 1000 seconds or more under an environment of extremely low temperature and high vacuum. By introducing a tunable UV laser to accumulated isolated molecular ions, we observed the detailed rotational and rotational spectra of them, which enabled us to explore cooling dynamics over a long period of time. We also succeeded in generating fast pulsed beams of large molecular and cluster ions for their accumulation, and neutral particles for collisions with accumulated ions.

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  • Real-time observation of radiative cooling of isolated molecular ions in RICE

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    NAKANO Yuji, KUMA Susumu

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    4 2016 - 3 2018

    Grant number:16K13859

    Grant amount:\3640000 ( Direct Cost: \2800000 、 Indirect Cost:\840000 )

    An in-ring predissociation spectroscopy of N2O+ molecular ions, A2Σ+←X2Π2/3 (000)-(200), has been carried out in the RIKEN Cryogenic Electrostatic ring (RICE). With the use of a dedicated detection system, rotational spectra of N2O+ were observed at different storage periods of from 250 microseconds to about 1 second. The real-time observation of rotational population distribution was successfully attained, and the change of rotational temperature was measured by comparing the experimental result to numerical simulations using the pgopher code.

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  • Superfluid helium droplet beam for exploring ultracold molecular dynamics

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    Kuma Susumu

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    4 2015 - 3 2017

    Grant number:15K17817

    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    Efficient cooling of molecules from room temperature and long-time observation of their properties are necessary to understand the characteristic molecular dynamics in the ultracold temperature. We proposed the new method to explore the low-temperature molecular dynamics by extending the experimental technique of superfluid helium droplets, that are at present the most ideal cold matrix medium. In this research period, we generated an intense, pulsed droplet beam consisting of micron-size helium droplets. These droplets have a enough capability of capturing small-size molecules to large, nano-clusters.

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  • Observation of free-electron-laser-induced collective spontaneous emission in soft x-ray region

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    SHIGEMASA Eiji, IWAYAMA Hiroshi, Harries J. R., FUJISE Hikaru, KUMA Susumu, TAMASAKU Kenji

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    4 2014 - 3 2017

    Grant number:26286080

    Grant amount:\15730000 ( Direct Cost: \12100000 、 Indirect Cost:\3630000 )

    In order to observe collective spontaneous emission (SF) in the short wavelength region, we have developed a new fluorescence spectrometer. Experiments have been carried out at BL1 of SACLA (X-ray free electron laser (FEL) facility) by using this spectrometer, which was set at the downstream of the beamline, for observing EUV radiation from excited helium atoms. The FEL wavelengths were set at 53.7 nm and 52.2 nm, which correspond to the 3p and 4p resonances.
    We have observed intense EUV radiation from excited helium atoms, emitted to the downstream of the beamline. At the both wavelengths, pulsed time structures for the radiation were observed, whose widths and delay times depend on the sample gas pressures. These trends agree with the general features of SF, but the pressure dependence of the peak intensity completely differs from what is expected for the SF. This may be due to the insufficient time resolution. A further work with much improved time resolution is scheduled.

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  • Detection of neutrino pairs using macro coherent amplification mechanism

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

    SASAO NOBORU, NAKANO Itsuo, YOSHIMURA Motohiko, FUKUMI Atsushi, WAKABAYASHI Tomonari, TANAKA Minoru, KATSURAGAWA Masayuki, NANJO Hajime, KAWAGUCHI Kentarou, TANG Jian, KUBOZONO Yoshihiro, TANIGAKI Katsumi, NAKAJIMA Kyo, YOSHIMURA Koji, YOSHIMI Akihiro, UETAKE Satoshi, KUMA Susumu, TANIGUCHI Takashi

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    4 2009 - 3 2015

    Grant number:21104002

    Grant amount:\411840000 ( Direct Cost: \316800000 、 Indirect Cost:\95040000 )

    "Macro-coherent amplification mechanism" is the crucial principle for success of the neutrino mass spectroscopy with atoms. The most important result of the present research was an experimental proof of the principle with a two photon process from the vibrationally excited state of para-hydrogen molecules. Actually, the initial coherent states were prepared by an adiabatic Raman process, and two photon emissions were observed. As a result, a gigantic enhancement factor of the photon yields greater than 15 orders of magnitude was confirmed compared to its natural emission rate; it was found consistent with the theoretical prediction. Thus a big step has been made forward towards the neutrino mass spectroscopy with atoms. In addition, detailed studies on super-radiance and phase relaxation etc. were conducted as basic studies using various atoms and molecules.

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  • ヘリウム液滴を用いた水素分子の超流動転移に関する研究

    日本学術振興会  科学研究費助成事業 

    久間 晋

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    2002 - 2004

    Grant number:02J01860

    Grant amount:\3000000 ( Direct Cost: \3000000 )

    極低温にあるヘリウム液滴中のマグネシウムフタロシアニン(Mg-Pc)分子の周りに、10個程度のアルゴン原子からなるクラスターを生成したときに、Mg-Pc分子のレーザー誘起蛍光(LIF)スペクトルの線幅が異常に広がることを観測した。昨年度まで、フタロシアニン分子とその周りの希ガス原子クラスターについて、同様の現象を観測しており、この現象は中心の分子種によらない、ファンデルワールスクラスターに共通の性質であると結論づけられた。過去に、10個程度の原子からなる少数クラスターが、低温でも液体として存在しうる可能性があることが理論的に示されている。また気相においては、少数クラスターの液体化によると考えられるスペクトルの線幅の広がりが、実験的に観測されている。液体クラスターに囲まれているため中心分子の位相緩和が速くなり、その結果として線幅が広がるのである。われわれが得た今回の結果は、0.4ケルビン以下という極低温のヘリウム液滴媒質中でも、少数クラスターの液体化が起こったことを示唆している。このことはヘリウム媒質の相互作用が非常に小さいこと、またさらに、ヘリウム液滴が超流動状態にあることから何らかの新しい効果がクラスターに作用していることを示すものである。
    さらに水素分子クラスターの場合には、LIFスペクトルの線幅の広がりに、液体クラスターとしての性質の変化を示す興味深い特徴が見られた。クラスターが大きくなるほど広がっていた線幅が、あるクラスターサイズでは逆に狭くなり始めた。そのサイズは、中心分子をひと回り取り囲むサイズの水素分子クラスターに対応している。このことは、過去の理論研究が示すように、適当なサイズのクラスターとして存在することで、水素分子が超流動転移を起こした可能性を示すものである。

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