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Last Updated :2024/11/20

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Master

Affiliation (Master)

  • Institute of Low Temperature Science　Frontier Ice and Snow Science

Affiliation (Master)

  • Institute of Low Temperature Science　Frontier Ice and Snow Science

researchmap

Profile and Settings

Affiliation

  • Hokkaido University, Institute of Low Temperature Science, Frontier Ice and Snow Science Section

Degree

  • Doctor of Science（Tokyo Institute of Technology）

Profile and Settings

  • Name (Japanese)

    Tsuge

  • Name (Kana)

    Masashi

  • Name

    P-1370-2019, 201601013526324046

Alternate Names

Affiliation

  • Hokkaido University, Institute of Low Temperature Science, Frontier Ice and Snow Science Section

Achievement

Research Interests

  • Astrochemistry   赤外分光   solid para-hydrogen   マトリックス単離法   laser spectroscopy   希ガス化合物   分子錯体   MALDI   フェムト秒レーザー   量子化学計算   

Research Areas

  • Natural sciences / Space and planetary science
  • Natural sciences / Bio-, chemical, and soft-matter physics
  • Nanotechnology/Materials / Basic physical chemistry

Research Experience

  • 2021/05 - Today Hokkaido University Institute of Low Temperature Science Frontier Ice and Snow Science Section Assistant Professor
  • 2017/08 - 2021/04 Hokkaido University Intsitute of Low Temperature Science Appointed Assistant Professor
  • 2014/01 - 2017/07 National Chiao Tung University Department of Applied Chemistry Postdoctoral Fellow
  • 2011/02 - 2013/12 University of Helsinki Department of Chemistry Postdoctoral Researcher
  • 2007/04 - 2011/01 Niigata University of Pharmacy and Applied Life Sciences Faculty of Pharmaceutical Sciences

Education

  • 2004/04 - 2007/03  Tokyo Institute of Technology  Graduate School of Science and Engineering
  • 2002/04 - 2004/03  Tokyo Institute of Technology  Graduate School of Science and Engineering
  • 1998/04 - 2002/03  Tokyo Institute of Technology  School of Science  Department of Chemistry

Published Papers

  • Kensei Kitajima, Yoichi Nakai, Masashi Tsuge, Naoki Watanabe
    The Journal of Physical Chemistry Letters 2024/11/15
  • Masashi Tsuge, Germán Molpeceres, Yuri Aikawa, Naoki Watanabe
    The Astrophysical Journal 973 (2) 80 - 80 0004-637X 2024/09/20 [Refereed][Not invited]
     
    Abstract Methane (CH4) is one of the major components of the icy mantle of cosmic dust prevalent in cold, dense regions of interstellar media, playing an important role in the synthesis of complex organic molecules and prebiotic molecules. Solid CH4 is considered to be formed via the successive hydrogenation of C atoms accreting onto dust: C + 4H → CH4. However, most astrochemical models assume this reaction on the ice mantles of dust to be barrierless and efficient, without considering the states of adsorption. Recently, we found that C atoms exist in either the physisorbed or chemisorbed state on compact amorphous solid water, which is analogous to an interstellar ice mantle. These distinct adsorption states considerably affect the hydrogenation reactivity of the C atom. Herein, we elucidate the reactivities of physisorbed and chemisorbed C atoms with H atoms via sequential deposition and codeposition processes. The results indicate that only physisorbed C atoms can produce CH4 on ice. Combining this finding with a previous estimate for the fraction of physisorbed C atoms on ice, we determined the upper limit for the conversion of C atoms into CH4 to be 30%.
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  • Ni-En Sie, Masashi Tsuge, Yoichi Nakai, Naoki Watanabe
    Chemical Physics Letters 848 141384 - 141384 0009-2614 2024/08 [Refereed][Not invited]
  • Germán Molpeceres, Masashi Tsuge, Kenji Furuya, Naoki Watanabe, David San Andrés, Víctor M. Rivilla, Laura Colzi, Yuri Aikawa
    The Journal of Physical Chemistry A 128 3874 - 3889 1089-5639 2024/05/06 [Refereed][Not invited]
  • Qingkuan Meng, Qiang Chang, Gang Zhao, Donghui Quan, Masashi Tsuge, Xia Zhang, Yong Zhang, Xiao-Hu Li
    Monthly Notices of the Royal Astronomical Society 526 (2) 2394 - 2399 0035-8711 2023/09/26 [Refereed][Not invited]
     
    ABSTRACT Recent experiments show that the desorption energy of H2 on a diamond-like carbon surface depends on the H2 coverage of the surface. We aim to quantitatively explain the coverage dependent H2 desorption energy measured by the experiments. We derive a math formula to calculate an effective H2 desorption energy based on the encounter desorption mechanism. The effective H2 desorption energy depends on two key parameters, the desorption energy of H2 on H2 substrate and the ratio of H2 diffusion barrier to its desorption energy. The calculated effective H2 desorption energy qualitatively agrees with the coverage dependent H2 desorption energy measured by the experiments if the values of these two parameters in literature are used in the calculations. We argue that the difference between the effective H2 desorption energy and the experimental results is due to the lack of knowledge about these two parameters. So, we recalculate these two parameters based on experimental data. Good agreement between theoretical and experimental results can be achieved if these two updated parameters are used in the calculations.
  • Masashi Tsuge, Germán Molpeceres, Yuri Aikawa, Naoki Watanabe
    Nature Astronomy 7 1351 - 1358 2023/09/14 [Refereed][Not invited]
     
    Many interstellar complex organic molecules (COMs) are believed to be produced on the surfaces of icy grains at low temperatures. Atomic carbon is considered responsible for the skeletal evolution processes, such as C–C bond formation, via insertion or addition reactions. Before reactions, C atoms must diffuse on the surface to encounter reaction partners; therefore, information on their diffusion process is critically important for evaluating the role of C atoms in the formation of COMs. In situ detection of C atoms on ice was achieved by a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods. We found that C atoms weakly bound to the ice surface diffused above approximately 30 K and produced C2 molecules. The activation energy for C-atom surface diffusion was experimentally determined to be 88 meV (1,020 K), indicating that the diffusive reaction of C atoms is activated at approximately 22 K on interstellar ice. The facile diffusion of C atoms at temperatures above 22 K on interstellar ice opens a previously overlooked chemical regime where the increase in complexity of COMs is driven by C atoms. Carbon addition chemistry can be an alternative source of chemical complexity in translucent clouds and protoplanetary disks with crucial implications in our current understanding on the origin and evolution of organic chemistry in our Universe.
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  • Masashi TSUGE, Naoki WATANABE
    Proceedings of the Japan Academy, Series B 99 (4) 103 - 130 0386-2208 2023/04/28 [Refereed][Invited]
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  • Prasad Ramesh Joshi, Masashi Tsuge, Chih-Yu Tseng, Yuan-Pern Lee
    Physical Chemistry Chemical Physics 25 11934 - 11950 1463-9076 2023/02/20 [Refereed][Not invited]
     
    Protonated polycyclic aromatic nitrogen heterocycles (H+PANH) are prospective candidates that might contribute to the interstellar unidentified infrared (UIR) emission bands because protonation enhances the relative intensities of bands near 6.2,...
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  • A. Miyazaki, M. Tsuge, H. Hidaka, Y. Nakai, N. Watanabe
    The Astrophysical Journal Letters 940 (1) L2 - L2 2041-8205 2022/11/01 [Refereed][Not invited]
     
    Abstract Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods, the behaviors of OH radicals on the surface of an interstellar ice analog were monitored at temperatures between 54 and 80 K. The OH number density on the surface of ultraviolet-irradiated compact amorphous solid water gradually decreased at temperatures above 60 K. Analyzing the temperature dependence of OH intensities with the Arrhenius equation, the decrease can be explained by the recombination of two OH radicals, which is rate-limited by thermal diffusion of OH. The activation energy for surface diffusion was experimentally determined for the first time to be 0.14 ± 0.01 eV, which is larger than or equivalent to those assumed in theoretical models. This value implies that the diffusive reaction of OH radicals starts to be activated at approximately 36 K on interstellar ice.
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  • Akira Kouchi, Takashi Shimonishi, Tomoya Yamazaki, Masashi Tsuge, Naoki Nakatani, Kenji Furuya, Hiromasa Niinomi, Yasuhiro Oba, Tetsuya Hama, Hiroyasu Katsuno, Naoki Watanabe, Yuki Kimura
    Chirality - New Insights [Working Title] 2022/08/22 [Refereed][Invited]
     
    We observed the formation of CO, CH3OH, and H2O ices using a cryogenic transmission electron microscope, to determine if chiral ice crystals could form under the conditions of interstellar molecular clouds and young stellar objects (protoplanetary disks) and to clarify the crystalline structure of these ices. Our results suggest that the following ice crystals are chiral: crystalline CO (α-CO) formed on amorphous H2O (a-H2O) grains in a 10-K molecular cloud, crystalline CH3OH formed by the heating of amorphous CH3OH on a-H2O grains at 40–60 K in young stellar objects, and several polymorphs of hydrogen-ordered cubic ice crystals formed by the heating of a-H2O at 80–100 K and direct condensation at 120–140 K in protoplanetary disks. We also investigated candidates for other chiral ices using published data. We found that NH3 I and NH3·H2O I are chiral at low temperature and pressure conditions. If one-handed circularly polarized light is irradiated during the nucleation of these chiral ice crystals, homochiral crystals can be formed. These results have important implications for the origin of interstellar organic molecule homochirality.
  • Isabelle Weber, Masashi Tsuge, Pavithraa Sundararajan, Masaaki Baba, Hidehiro Sakurai, Yuan-Pern Lee
    The Journal of Physical Chemistry A 126 (32) 5283 - 5293 1089-5639 2022/08/18 [Refereed][Not invited]
  • Masashi Tsuge, Akira Kouchi, Naoki Watanabe
    The Astrophysical Journal 933 (2) 138 - 138 0004-637X 2022/07/01 [Refereed][Not invited]
     
    Abstract Chemical processes on the surface of icy grains play an important role in the chemical evolution in molecular clouds. In particular, reactions involving nonenergetic hydrogen atoms accreted from the gaseous phase have been extensively studied. These reactions are believed to effectively proceed only on the surface of the icy grains; thus, molecules embedded in the ice mantle are not considered to react with hydrogen atoms. Recently, Tsuge et al. suggested that nonenergetic hydrogen atoms can react with CO molecules even in ice mantles via diffusive hydrogenation. This investigation was extended to benzene and naphthalene molecules embedded in amorphous solid water (ASW) in the present study, which revealed that a portion of these molecules could be fully hydrogenated in astrophysical environments. The penetration depths of nonenergetic hydrogen atoms into porous and nonporous ASW were determined using benzene molecules to be >50 and ∼10 monolayers, respectively (1 monolayer ≈ 0.3 nm).
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  • W. M. C. Sameera, Bethmini Senevirathne, Thanh Nguyen, Yasuhiro Oba, Atsuki Ishibashi, Masashi Tsuge, Hiroshi Hidaka, Naoki Watanabe
    Frontiers in Astronomy and Space Sciences 9 890161  2022/05/30 [Refereed][Invited]
     
    Heterogeneous radical processes on ice surfaces play a vital role in the formation of building blocks of the biologically relevant molecules in space. Therefore, quantitative mechanistic details of the radical binding and radical reactions on ices are crucial in rationalizing the chemical evolution in the Universe. The radical chemistry on ice surfaces was explored at low temperatures by combining quantum chemical calculations and laboratory experiments. A range of binding energies was observed for OH, HCO, CH3, and CH3O radicals binding on ices. Computed reaction paths of the radical reactions on ices, OCS + H and PH3 + D, explained the experimentally observed products. In both radical reactions, quantum tunnelling plays a key role in achieving the reactions at low temperatures. Our findings give quantitative insights into radical chemistry on ice surfaces in interstellar space and the planetary atmospheres.
  • Akira Kouchi, Yuki Kimura, Kensei Kitajima, Hiroyasu Katsuno, Hiroshi Hidaka, Yasuhiro Oba, Masashi Tsuge, Tomoya Yamazaki, Kazuyuki Fujita, Tetsuya Hama, Yukihiro Takahashi, Shunichi Nakatsubo, Naoki Watanabe
    Frontiers in Chemistry 9 799851 - 799851 2021/12/08 [Refereed][Not invited]
     
    The occurrence of hydrogen atom-ordered form of ice Ih, ice XI, in the outer Solar System has been discussed based on laboratory experiments because its ferroelectricity influences the physical processes in the outer Solar System. However, the formation of ice XI in that region is still unknown due to a lack of formation conditions at temperatures higher than 72 K and the effect of UV-rays on the phase transition from ice I to ice XI. As a result, we observed the UV-irradiation process on ice Ih and ice Ic using a newly developed ultra-high vacuum cryogenic transmission electron microscope. We found that ice Ih transformed to ice XI at temperatures between 75 and 140 K with a relatively small UV dose. Although ice Ic partially transformed to ice XI at 83 K, the rate of transformation was slower than for ice Ih. These findings point to the formation of ice XI at temperatures greater than 72 K via UV irradiation of ice I crystals in the Solar System; icy grains and the surfaces of icy satellites in the Jovian and Saturnian regions.
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  • Masashi Tsuge, Akira Kouchi, Naoki Watanabe
    The Astrophysical Journal 923 (1) 71  0004-637X 2021/12/01 [Refereed][Not invited]
     
    Abstract Hydrogen molecules have two nuclear spin isomers: ortho-H2 and para-H2. The ortho-to-para ratio (OPR) is known to affect chemical evolution as well as gas dynamics in space. Therefore, understanding the mechanism of OPR variation in astrophysical environments is important. In this work, the nuclear spin conversion (NSC) processes of H2 molecules on diamond-like carbon and graphite surfaces are investigated experimentally by employing temperature-programmed desorption and resonance-enhanced multiphoton ionization methods. For the diamond-like carbon surface, the NSC time constants were determined at temperatures of 10–18 K and from 3900 ± 800 s at 10 K to 750 ± 40 s at 18 K. Similar NSC time constants and temperature dependence were observed for a graphite surface, indicating that bonding motifs (sp3 or sp2 hybridization) have little effect on the NSC rates.
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  • Kennosuke Hoshina, Tatsuro Shirota, Masashi Tsuge
    The Journal of Physical Chemistry A 125 (43) 9508 - 9517 1089-5639 2021/11/04 [Refereed][Not invited]
  • Akira Kouchi, Masashi Tsuge, Tetsuya Hama, Yasuhiro Oba, Satoshi Okuzumi, Sin-iti Sirono, Munetake Momose, Naoki Nakatani, Kenji Furuya, Takashi Shimonishi, Tomoya Yamazaki, Hiroshi Hidaka, Yuki Kimura, Ken-ichiro Murata, Kazuyuki Fujita, Shunichi Nakatsubo, Shogo Tachibana, Naoki Watanabe
    The Astrophysical Journal 918 (2) 45 - 45 0004-637X 2021/09/06 [Refereed][Not invited]
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  • Akira Kouchi, Masashi Tsuge, Tetsuya Hama, Hiromasa Niinomi, Naoki Nakatani, Takashi Shimonishi, Yasuhiro Oba, Yuki Kimura, Sin-iti Sirono, Satoshi Okuzumi, Munetake Momose, Kenji Furuya, Naoki Watanabe
    Monthly Notices of the Royal Astronomical Society 505 (1) 1530 - 1542 0035-8711 2021/04/27 [Refereed][Not invited]
     
    Abstract The crystallinity and morphology of solid CO on icy interstellar grains were examined by observing the deposition, crystallisation, and UV and electrons irradiation of solid CO using transmission electron microscopy. Herein, we found that solid CO deposited in molecular clouds was crystalline, and that even if amorphous CO was deposited amorphous CO crystallised within 103 years at 10 K. Conversely, crystalline CO was not amorphised by UV rays or electron beam at 10 K. These results indicated the occurrence of chiral crystalline CO instead of amorphous CO in space. Furthermore, the large surface diffusion coefficients of CO on amorphous H2O and crystalline CO at 10 K facilitated the morphological equilibration of crystalline CO. Bad wetting of crystalline CO with amorphous H2O proved that the morphology of the ice grains was not spherical with an onion-like structure, as hitherto assumed, but rather it was a polyhedral crystalline CO attached to amorphous H2O. This has important implications for phenomena associated with the collision and subsequent sticking between ice grains, surface chemical reactions, non-thermal desorption of molecules and the origin of homochirality in interstellar biomolecules.
  • M. Tsuge, T. Namiyoshi, K. Furuya, T. Yamazaki, A. Kouchi, N. Watanabe
    The Astrophysical Journal 908 (2) 234 - 234 0004-637X 2021/02/26 [Refereed][Not invited]
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  • Masashi Tsuge, Naoki Watanabe
    Accounts of Chemical Research 54 (3) 471 - 480 2021/02/02 [Refereed][Invited]
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  • Kensei Kitajima, Yoichi Nakai, W. M. C. Sameera, Masashi Tsuge, Ayane Miyazaki, Hiroshi Hidaka, Akira Kouchi, Naoki Watanabe
    The Journal of Physical Chemistry Letters 12 (1) 704 - 710 1948-7185 2021/01/14 [Refereed][Not invited]
  • A. Miyazaki, N. Watanabe, W. M. C. Sameera, Y. Nakai, M. Tsuge, T. Hama, H. Hidaka, A. Kouchi
    Physical Review A 102 (5) 52822  2469-9926 2020/11/20 [Refereed][Not invited]
  • Masashi Tsuge, Yu-Hsuan Chen, Yuan-Pern Lee
    The Journal of Physical Chemistry A 124 (37) 7500 - 7510 1089-5639 2020/09/17 [Refereed][Not invited]
  • Masashi Tsuge, Thanh Nguyen, Yasuhiro Oba, Tetsuya Hama, Akira Kouchi, Naoki Watanabe
    Chemical Physics Letters 760 137999 - 137999 0009-2614 2020/09/14 [Refereed][Not invited]
  • Masashi Tsuge, Hiroshi Hidaka, Akira Kouchi, Naoki Watanabe
    The Astrophysical Journal 900 187  2020/09/01 [Refereed][Not invited]
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  • Daniel Leicht, Brandon M. Rittgers, Gary E. Douberly, J. Philipp Wagner, David C. McDonald, II, Daniel T. Mauney, Masashi Tsuge, Yuan-Pern Lee, Michael A. Duncan
    The Journal of Chemical Physics 153 (8) 84305 - 84305 0021-9606 2020/08/28 [Refereed][Not invited]
  • Naoki Watanabe, Masashi Tsuge
    Journal of the Physical Society of Japan 89 51015  2020/05/15 [Refereed][Invited]
  • Masashi Tsuge, Yu-Hsuan Chen, Yuan-Pern Lee
    The Journal of Physical Chemistry A 124 (11) 2253 - 2263 2020/03/19 [Refereed][Not invited]
  • Masashi Tsuge, Markku Räsänen, Leonid Khriachtchev
    Chemical Physics Letters 739 136987 - 136987 2020/01 [Refereed][Not invited]
     
    The thermal decomposition process of HXeCl···H2O in solid Xe is studied, and HCl···H2O is identified as a decomposition product. The production is due to the two-body (2B) decomposition of HXeCl moiety, in agreement with theoretical predictions. Two types of 2B decomposition paths are predicted: catalytic and unimolecular 2B decompositions, where water molecule plays different roles. In an experiment to selectively produce HXeCl···D2O, only HCl···D2O is observed as a thermal decomposition product, indicating the occurrence of unimolecular 2B decomposition, where water molecule serves as a spectator. The activation energy for this decomposition process is experimentally determined to be 15 kJ mol−1.
  • Ayumi Kanaoka, Hiromi Tohyama, Sachi Kunishige, Toshiharu Katori, Akiko Nishiyama, Masatoshi Misono, Naofumi Nakayama, Hidehiro Sakurai, Masashi Tsuge, Masaaki Baba
    The Journal of Chemical Physics 151 (23) 234305  0021-9606 2019/12/21 [Refereed][Not invited]
     
    © 2019 Author(s). Corannulene is a nonplanar aromatic hydrocarbon also known as a buckybowl. Its electronic and vibrational structure has been investigated by analyzing its fluorescence excitation spectrum and dispersed fluorescence spectrum in a supersonic jet. Its spectral features are in keeping with the expectation, confirmed by some previous results, that it has fivefold or C5v symmetry. The observed prominent vibronic bands in the S1 ← S0 transition have been assigned to e1 and e2 bands on the basis of theoretical calculations so that the S1 state was assigned to 1E2. The symmetry adapted cluster configuration interaction calculation supports this assignment of the S1 electronic state, although the time-dependent density functional theory calculation suggests that the S1 state is 1A2. It has also been shown that the normal coordinates for strong vibronic bands mainly include out-of-plane vibrational motion. The rotational envelopes are well explained by taking account of the Coriolis interaction between the degenerate vibrational and rotational levels. The mechanism of bowl-to-bowl inversion is also discussed with the results of theoretical calculations regarding the barrier to inversion and metastable conformation.
  • Pavithraa Sundararajan, Masashi Tsuge, Masaaki Baba, Hidehiro Sakurai, Yuan-Pern Lee
    The Journal of Chemical Physics 151 (4) 44304  0021-9606 2019/07/28 [Refereed][Not invited]
     
    © 2019 Author(s). Hydrogenated polycyclic aromatic hydrocarbons have been proposed to be carriers of the interstellar unidentified infrared (UIR) emission bands and the catalysts for formation of H2; spectral characterizations of these species are hence important. We report the infrared (IR) spectrum of mono-hydrogenated corannulene (HC20H10) in solid para-hydrogen (p-H2). In experiments of electron bombardment of a mixture of corannulene and p-H2 during deposition of a matrix at 3.2 K, two groups of spectral lines increased with time during maintenance of the matrix in darkness after deposition. Lines in one group were assigned to the most stable isomer of hydrogenated corannulene, rim-HC20H10, according to the expected chemistry and a comparison with scaled harmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. The lines in the other group do not agree with predicted spectra of other HC20H10 isomers and remain unassigned. Alternative hydrogenation was achieved with H atoms produced photochemically in the infrared-induced reaction Cl + H2 (v = 1) → H + HCl in a Cl2/C20H10/p-H2 matrix. With this method, only lines attributable to rim-HC20H10 were observed, indicating that hydrogenation via a quantum-mechanical tunneling mechanism produces preferably the least-energy rim-HC20H10 regardless of similar barrier heights and widths for the formation of rim-HC20H10 and hub-HC20H10. The mechanisms of formation in both experiments are discussed. The bands near 3.3 and 3.4 μm of rim-HC20H10 agree with the UIR emission bands in position and relative intensity, but other bands do not match satisfactorily with the UIR bands.
  • Masashi Tsuge, Tetsuya Hama, Yuki Kimura, Akira Kouchi, Naoki Watanabe
    The Astrophysical Journal 878 (1) 23  0004-637X 2019/06/10 [Refereed][Not invited]
     
    The interactions of atomic and molecular hydrogen with bare interstellar dust grain surfaces are important for understanding H-2 formation at relatively high temperatures (>20 K). We investigate the diffusion of physisorbed H atoms and the desorption energetics of H-2 molecules on an amorphous diamond-like carbon (DLC) surface. From temperature-programmed desorption experiments with a resonance-enhanced multiphoton ionization (REMPI) method for H-2 detection, the H-2 coverage-dependent activation energies for H-2 desorption are determined. The activation energies decrease with increasing H-2 coverage and are centered at 30 meV with a narrow distribution. Using a combination of photostimulated desorption and REMPI methods, the time variations of the surface number density of H-2 following atomic and molecular hydrogen depositions are studied. From these measurements, we show that H-2 formation on a DLC surface is quite efficient, even at 20 K. A significant kinetic isotope effect for H-2 and D-2 recombination reactions suggests that H-atom diffusion on a DLC surface is mediated by quantum mechanical tunneling. In astrophysically relevant conditions, H-2 recombination due to physisorbed H-atoms is unlikely to occur at 20 K, suggesting that chemisorbed H atoms might play a role in H-2 formation at relatively high temperatures.
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  • Pavithraa Sundararajan, Masashi Tsuge, Masaaki Baba, Yuan-Pern Lee
    ACS Earth and Space Chemistry 2 (10) 1001 - 1010 2018/10/18 [Refereed][Not invited]
  • Enrique Mendez‐Vega, Mika Maehara, Akshay Hemant Raut, Joel Mieres‐Perez, Masashi Tsuge, Yuan‐Pern Lee, Wolfram Sander
    Chemistry–A European Journal 24 (70) 18801 - 18808 2018/10/12 [Refereed][Not invited]
  • Masashi Tsuge, Chia-Peng Lai, Yuan-Pern Lee
    The Journal of Chemical Physics 149 14306  2018/07/07 [Refereed][Not invited]
  • Y. Kimura, M. Tsuge, V. Pirronello, A. Kouchi, N. Watanabe
    The Astrophysical Journal Letters 858 (2) 2041-8213 2018/05/10 [Refereed][Not invited]
     
    The diffusion of hydrogen atoms on dust grains is a key process in the formation of interstellar H2 and some hydrogenated molecules such as formaldehyde and methanol. We investigate the adsorption and diffusion of H atoms on pure solid CO as an analog of dust surfaces observed toward some cold interstellar regions. Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods to detect H atoms directly, the relative adsorption probabilities and diffusion coefficients of the H atoms are measured on pure solid CO at 8, 12, and 15 K. There is little difference between the diffusion coefficients of the hydrogen and deuterium atoms, indicating that the diffusion is limited by thermal hopping. The activation energies controlling the H-atom diffusion depend on the surface temperature, and values of 22, 30, and ∼37 meV were obtained for 8, 12, and 15 K, respectively.
  • Masashi Tsuge, Chih-Yu Tseng, Yuan-Pern Lee
    Physical Chemistry Chemical Physics 20 (8) 5344 - 5358 1463-9076 2018 [Refereed][Not invited]
     
    para-Hydrogen (p-H2) serves as a new host in matrix-isolation experiments for an investigation of species of astrochemical interest. Protonated and mono-hydrogenated species are produced upon electron bombardment during deposition of p-H2 containing a precursor in a small proportion. The applications of this novel technique to generate protonated polycyclic aromatic hydrocarbons (H+PAH), protonated polycyclic nitrogen heterocycles (H+PANH), and their neutral counterparts, which are important in the identification of interstellar unidentified infrared emission bands, demonstrate its superiority over other methods. The clean production with little fragmentation, ease of distinction between protonated and neutral species, narrow lines and reliable relative infrared intensities of the lines, and broad coverage of the spectral range associated with this method enable us to assign the isomers unambiguously. The application of this method to the protonation of small molecules is more complicated partly because of the feasible fragmentation and reactions, and partly because of the possible proton sharing between the species of interest and H2, but, with isotopic experiments and secondary photolysis, definitive assignments are practicable. Furthermore, the true relative infrared intensities are critical to a comparison of experimental results with data from theoretical calculations. The spectra of a proton-shared species in solid p-H2 might provide insight into a search for spectra of proton-bound species in interstellar media. Investigations of hydrogenated species involving the photolysis of Cl2 or precursors of OH complement those using electron bombardment and provide an improved ratio of signal to noise. With careful grouping of observed lines after secondary photolysis and a comparison with theoretical predictions, various isomers of these species have been determined. This photolytic technique has been applied in an investigation of hydrogenated PAH and PANH, and the hydrogenation reactions of small molecules, which are important in interstellar ice and the evolution of life. The electronic transitions of molecules in solid p-H2 have been little investigated. The matrix shift of the origins of transitions and the spectral width seem to be much smaller than those of noble-gas matrices these features might facilitate a direct comparison of matrix spectra with diffuse interstellar bands, but further data are required to assess this possibility. The advantages and disadvantages of applying these techniques of p-H2 matrix isolation to astrochemical research and their future perspectives are discussed.
  • Hsin-Yi Liao, Masashi Tsuge, Jake A. Tan, Jer-Lai Kuo, Yuan-Pern Lee
    Physical Chemistry Chemical Physics 19 (31) 20484 - 20492 1463-9076 2017/07/13 [Refereed][Not invited]
     
    The proton-bound nitrogen dimer, N-2-H+-N-2, and its isotopologues were investigated by means of vibrational spectroscopy. These species were produced upon electron bombardment of mixtures of N-2 (or N-15(2)) and para-hydrogen (p-H-2) or normal-D-2 (n-D-2) during deposition at 3.2 K. Reduced-dimension anharmonic vibrational Schrodinger equations were constructed to account for the strong anharmonic effects in these protonated species. The fundamental lines of proton motions in N-2-H+-N-2 were observed at 715.0 (NH+N antisymmetric stretch, nu(4)), 1129.6 (NH+N bend, nu(6)), and 2352.7 (antisymmetric NN/NN stretch, nu(3)) cm(-1), in agreement with values of 763, 1144, and 2423 cm(-1) predicted with anharmonic calculations using the discrete-variable representation (DVR) method at the CCSD/aug-cc-pVDZ level. The lines at 1030.2 and 1395.5 cm(-1) were assigned to combination bands involving n nu(2) + n4 (n = 1 and 2) according to theoretical calculations; nu(2) is the N-2 ... N-2 stretching mode. For N-15(2)-H+-N-15(2) in solid p-H-2, the corresponding major lines were observed at 710.0 (nu(4)), 1016.7 (nu(2) + nu(4)), 1124.3 (nu(6)), 1384.8 (2 nu(2) + nu(4)), and 2274.9 (nu(3)) cm(-1). For N-2-D+-N-2 in solid n-D-2, the corresponding major lines were observed at 494.0 (nu(4)), 840.7 (nu(2) + nu(4)), 825.5 (nu(6)), and 2356.2 (nu(3)) cm(-1). In addition, two lines at 762.0 (weak) and 808.3 cm(-1) were tentatively assigned to be some modes of N-2-H+-N-2 perturbed or activated by a third N-2 near the proton.
  • Masashi Tsuge, Yuan-Pern Lee
    Physical Chemistry Chemical Physics 19 (14) 9641 - 9653 1463-9076 2017/05/13 [Refereed][Not invited]
     
    We report infrared (IR) spectra of HSCS+, c-HSCS, HCS2-, and other species produced on electron bombardment of a mixture of CS2 and para-hydrogen (p-H-2) during deposition at 3.2 K. After maintenance of the deposited matrix in darkness for 12 h, the intensities of the absorption lines of HSCS+ at 2477.2 (v(1)), 1525.6 (v(2)), and 919.6 cm(-1) (v(3)) decreased through neutralization of HSCS+ with trapped electrons. During this period, the intensities of the lines of HCS2- at 2875.7 (v(1)), 1249.9 (v(5)), 1003.2 (v(6)), and 814.3 cm (1) (v(4)) increased due to reaction between H and CS2 . The intensities of the lines observed at 2312.7 and 889.0 cm(-1), which are assigned to the c-HSCS radical, increased after maintenance in darkness and greatly diminished after irradiation at 373 nm. The IR spectra of HSCS+, HCS2-, and c-HSCS are reported for the first time. The IR absorption lines of the t-HSCS radical, t-HC(S) SH, and c-HC(S) SH were also identified; their wavenumbers are similar to those reported for these species in an Ar matrix. The corresponding spectra of the C-13, S-34, and D isotopic variants of these species were observed. The assignments were made according to the expected chemical behavior, predicted potential energies of associated reactions, and a comparison of observed and predicted wavenumbers and their C-13, S-34, and D isotopic ratios. In contrast to the observed significant red shifts of the OH-stretching wavenumbers of HOCO+ and HOCS+ in solid p-H-2 compared to those in the gaseous phase due to proton sharing with H-2, the wavenumber of the HS-stretching mode of HSCS+ in solid p-H-2 (2477.2 cm(-1)) is similar to the anharmonic wavenumber of HSCS+ (2424 cm(-1)) predicted with the B3LYP/aug-cc-pVTZ method, indicating that the sharing of a proton between HSCS+ and neighboring H-2 molecules is insignificant.
  • Tatsuro Shirota, Masashi Tsuge, Yasumasa Hikosaka, Koichi Soejima, Kennosuke Hoshina
    JOURNAL OF PHYSICAL CHEMISTRY A 121 (1) 31 - 39 1089-5639 2016/12/09 [Refereed][Not invited]
     
    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.
  • Masashi Tsuge, Yuan-Pern Lee
    The Journal of Chemical Physics 145 (16) 164308 - 164308 0021-9606 2016/10/28 [Refereed][Not invited]
     
    We report infrared (IR) spectra of HOCS+, HSCO+, t-HOCS, and other species produced on electron bombardment of a mixture of carbonyl sulfide (OCS) and para-hydrogen (p-H-2) during deposition at 3.2 K. After maintenance of the matrix in darkness for 15 h, the intensities of absorption features of HOCS+ at 2945.9 (nu(1)), 1875.3 (nu(2)), and 1041.9 (nu(3)) cm(-1) and those of HSCO+ at 2506.9 (nu(1)) and 2074.2 (nu(2)) cm(-1) decreased through neutralization with trapped electrons. Lines observed at 3563.4, 1394.8, and 1199.0 cm(-1), which decreased slightly in intensity after maintenance in darkness and were nearly depleted after irradiation at 373 nm, are assigned to a t-HOCS radical. The corresponding spectra of their C-13- and D-isotopologues were observed. The IR spectra of HSCO+ and t-HOCS and those of modes nu(2) and nu(3) of HOCS+ are new. The assignments were made according to the expected chemical behavior and a comparison of experimental and calculated wavenumbers and C-13- and D-isotopic shifts. The wavenumber of the OH stretching mode (2945.9 cm(-1)) of HOCS+ in solid p-H-2 is significantly red-shifted from that (3435.16 cm(-1)) reported for gaseous HOCS+; this shift is attributed to partial sharing of a proton between OCS and H-2. The corresponding p-H-2 induced shift is small in HSCO+ because of a much weaker interaction between HSCO+ and H-2. Published by AIP Publishing.
  • Masashi Tsuge
    Physical Chemistry Chemical Physics 18 (41) 28864 - 28871 1463-9076 2016/09/22 [Refereed][Not invited]
     
    We report the infrared (IR) spectra of ovalene (C32H14) and hydrogenated ovalene (C32H15 center dot) in solid para-hydrogen (p-H-2). The hydrogenated ovalene and protonated ovalene were generated from electron bombardment of a mixture of ovalene and p-H-2 during deposition of a matrix at 3.2 K. The features that decreased with time have been previously assigned to 7-C32H15+, the most stable isomer of protonated ovalene (Astrophys. J., 2016, 825, 96). The spectral features that increased with time are assigned to the most stable isomer of hydrogenated ovalene (7-C32H15 center dot) based on the expected chemistry and on a comparison with the vibrational wavenumbers and IR intensities predicted by the B3PW91/6-311++ G(2d, 2p) method. The mechanism of formation of 7-C32H15 center dot is discussed according to the observed changes in intensity and calculated energetics of possible reactions of H + C32H14 and isomerization of C32H15 center dot. The formation of 7-C32H15 center dot is dominated by the reaction H + C32H14 -> 7-C32H15 center dot, implying that, regardless of the presence of a barrier, the hydrogenation of polycyclic aromatic hydrocarbons occurs even at 3.2 K.
  • Prasanta Das, Masashi Tsuge, Yuan-Pern Lee
    The Journal of Chemical Physics 145 (1) 014306 - 014306 0021-9606 2016/07/07 [Refereed][Not invited]
     
    We have employed electron bombardment during matrix deposition of CO2 (or (CO2)-C-13, (CO2)-O-18) and para-hydrogen (p-H-2) at 3.2 K and recorded infrared (IR) spectra of t-HOCO+, H+(CO2)(2) , HCO2-, CO2-, t-HOCO, and other species isolated in solid p-H-2. After the matrix was maintained in darkness for 13 h, intensities of absorption features of t-HOCO+ at 2403.5 (v(1)), 2369.9 (v(2)), 1018.1 (v(4)), and 606.5 (v(6)) cm(-1) and those of H+(CO2)(2) at 1341.1, 883.6, and 591.5 cm(-1) decreased. Corresponding lines of isotopologues were observed when (CO2)-C-13 or (CO2)-O-18 replaced CO2. In contrast, lines of HCO2- at 2522.4 (v(1)), 1616.1 (v(5)), 1327.9 (v(2)), and 745.6 (v(3)) cm(-1) increased in intensity; corresponding lines of (HCO2-)-C-13 or (HCO2-)-O-18 were also observed. Lines of t-DOCO+ and DCO2- were observed in an electron bombarded CO2/normal-deuterium (n-D-2) matrix. Data of v(6) of t-HOCO+ and all observed modes of (HOCO+)-O-18-O-18 and (HCO2-)-O-18 are new. The assignments were made according to expected chemical behavior, observed isotopic shifts, and comparisons with vibrational wavenumbers and relative intensities of previous reports and calculations with the B3PW91/aug-cc-pVQZ method. The v(1) line of t-HOCO+ in solid p-H-2 (2403.5 cm(-1)), similar to the line at 2673 cm(-1) of t-HOCO+ tagged with an Ar atom, is significantly red-shifted from that reported for gaseous t-HOCO+ (3375.37 cm(-1)) due to partial proton sharing between CO2 and H-2 or Ar. The v(1) line of HCO2- in solid p-H-2 (2522.4 cm(-1)) is blue shifted from that reported for HCO2- in solid Ne (2455.7 cm(-1)) and that of HCO2- tagged with Ar (2449 cm(-1)); this can be explained by the varied solvation effects by Ne, Ar, or H-2 on the mixing of H+ + CO2 and H+ CO2- surfaces. Possible formation mechanisms of t-HOCO+, H+(CO2)(2), HCO2-, CO2-, t-HOCO, H2O, and t-HCOOH are discussed. Published by AIP Publishing.
  • Masashi Tsuge
    The Astrophysical Journal 825 (2) 96  0004-637X 2016/07/06 [Refereed][Not invited]
     
    The mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H(+)PAHs) were proposed as possible carriers, but no spectrum of an H(+)PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C32H15+) measured in a para-hydrogen (p-H-2) matrix at 3.2 K, generated by bombarding a mixture of ovalene and p-H-2 with electrons during matrix deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d, 2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.
  • Masashi Tsuge
    JOURNAL OF PHYSICAL CHEMISTRY A 120 (19) 3380 - 3389 1089-5639 2016/04/26 [Refereed][Not invited]
     
    First-principles anharmonic calculations are carried out for the CH stretching vibrations of isolated toluene and compared with the experimental infrared spectra of isotopologues of toluene in a Ne matrix at 3 K and of liquid toluene at room temperature. The calculations use the vibrational self-consistent field method and the B3LYP potential surface. In general, good agreement is found between the calculations and experiments. However, the spectrum of toluene in a Ne matrix is more complicated than that predicted theoretically. This distinction is discussed in terms of matrix-site and resonance effects. Interestingly, the strongest peak in the CH stretching spectrum has similar widths in the liquid phase and in a Ne matrix, despite the very different temperatures. Implications of this observation to the broadening mechanism are discussed. Finally, our results show that the B3LYP potential offers a good description of the anharmonic CH stretching band in toluene, but a proper description of matrix-site and resonance effects remains a challenge.
  • Tomoki Nakayama, Kei Sato, Masashi Tsuge, Takashi Imamura, Yutaka Matsumi
    Journal of Geophysical Research 120 (15) 7777 - 7787 2156-2202 2015/07/15 [Refereed][Not invited]
     
    We report the firstmeasurements of the complex refractive index (RI) at 375, 405, 532, and 781 nm for secondary organic aerosol (SOA) generated from isoprene/NOx photooxidation. At all wavelengths studied, slightly greater real components of the RI were observed for the SOA generated in the absence of SO2 compared with those generated in its presence. Considering the chemical properties, the differences in the oxidation state and/or ratio of particle density to molecular weight of compounds in the SOA are considered to be the main factors determining the real components. The imaginary components at ≤532 nm were found to increase with increasing initial SO2 concentration. The highly conjugated oligomers are suggested to be plausible chromophore candidates. This study suggests that when large amounts of SOA are generated after mixing of isoprene with NOx and SOx, light absorption of these SOAs may compete with that of black carbon, especially at ultraviolet wavelengths.
  • Zhu, C., Tsuge, M., R{\"a}s{\"a}nen, M., Khriachtchev, L.
    Journal of Chemical Physics 142 (14) 144306  0021-9606 2015/04/13 [Refereed][Not invited]
     
    The HXeI center dot center dot center dot HCl and HXeI center dot center dot center dot HCCH complexes are studied computationally and experimentally in a Xe matrix. In the experiments, three bands of the HXeI center dot center dot center dot HCl complex and one band of the HXeI center dot center dot center dot HCCH complex in the H-Xe stretching region are observed. The monomer-to-complex shifts are + 94, + 111, and + 155 cm(-1) for the HXeI center dot center dot center dot HCl complex and + 49 cm(-1) for the HXeI center dot center dot center dot HCCH complex. The bands of the complexed HCl molecules are also observed with large red shifts from the HCl monomer (-187, -252, and -337 cm(-1)). The ab initio calculations at the CCSD(T)/def2-TZVPPD level of theory predict two stable structures for the HXeI center dot center dot center dot HCl complex with interaction energies of -3.72 and -0.28 kcal mol(-1) and one structure for the HXeI center dot center dot center dot HCCH complex with an interaction energy of -2.67 kcal mol(-1) and the calculated monomer-to-complex shifts are in a good agreement with experiment (in the case of HXeI center dot center dot center dot HCl, for the stronger structure). The HXeI molecules are decomposed by broad-band infrared light; however, the decomposition is much more efficient for the HXeI monomer than for the complexes studied here as well as for the previously studied HXeI center dot center dot center dot HI and HXeI center dot center dot center dot HBr complexes. In fact, the decomposition efficiency decreases as the monomer-to-complex shift of the H-Xe stretching mode increases. (C) 2015 AIP Publishing LLC.
  • Tsuge, M., Khriachtchev, L.
    Journal of Physical Chemistry A 119 (11) 2628 - 2635 1089-5639 2015/03/01 [Refereed][Not invited]
     
    We have studied hydrogen-atom tunneling in the cis-to-trans conformational change of some carboxylic acid monomers and formic acid (FA) complexes and dimers at the MP2(full) and CCSD(T) levels of theory within the Wentzel-Kramers-Brillouin approximation. The barrier for the minimum energy path, where the OH bond length and the COH bending angle are optimized, is found to be a good approximation for providing the highest barrier transparency. The matrix effect on the transmission coefficients of cis-FA monomer, trans-cis FA dimer (tc1), and cis-acetic acid monomer are modeled by the polarizable continuum model (PCM) at the MP2(full) level of theory in different environments. For the cis-FA monomer and trans-cis FA dimer (tc1), the calculated transmission coefficients agree with the experimental lifetimes observed in noble-gas solids. However, this method cannot reproduce the experimental results obtained for cis-acetic acid. Moreover, the long lifetime of cis-FA and cis-acetic acid in the N-2 environment cannot be reproduced either, which is most probably due to specific interactions that are not included in the PCM. The calculation for cis-HCOOD shows a strong decrease of the barrier transparency compared to that for cis-HCOOH, which is consistent with the experiments. In general, good agreement is observed between the calculated barrier transparency (including PCM) and experimental tunneling rate. However, some exceptions are found, which shows that additional factors influence the tunneling rate.
  • Amada, M., Sato, Y., Tsuge, M., Hoshina, K.
    Chemical Physics Letters 624 24 - 28 0009-2614 2015/02/11 [Refereed][Not invited]
     
    Fragment ions produced after the ionization of the acetic acid dimer (CH3COOH)(2) in a near-infrared intense femtosecond laser field were measured using time-of-flight mass spectrometry. The two-body Coulomb explosion (CE) process (CH3COOH)(2)(2+) -> 2CH(3)COOH(+) with a kinetic energy release of 3.4 eV, similar to the case of (HCOOH)(2)(2+) (Hoshina et al., 2012), was identified. The two-body CE of (CH3COOH)(2)(2+) was induced when the laser polarization direction was perpendicular to the C center dot center dot center dot C intermolecular axisin contrast to the case of (HCOOH)(2)(2+). The preferential configurations may be those that deform dimer structures close to dimer dications during the double-ionization process. (C) 2015 Elsevier B.V. All rights reserved.
  • Zhu, C., Niimi, K., Taketsugu, T., Tsuge, M., Nakayama, A., Khriachtchev, L.
    Journal of Chemical Physics 142 (5) 54305  0021-9606 2015/02/04 [Refereed][Not invited]
     
    Experimental and theoretical studies of HXeI and HXeH molecules in Ar, Kr, and Xe matrices are presented. HXeI exhibits the H-Xe stretching bands at 1238.0 and 1239.0 cm(-1) in Ar and Kr matrices, respectively, that are blue-shifted from the HXeI band observed in a Xe matrix (1193 cm(-1)) by 45 and 46 cm(-1). These shifts are larger than those observed previously for HXeCl (27 and 16 cm(-1)) and HXeBr (37 and 23 cm(-1)); thus, the matrix effect is stronger for less stable molecules. The results for HXeI are qualitatively different from all previous results on noble-gas hydrides with respect to the frequency order between Ar and Kr matrices. For previously studied HXeCl, HXeBr, and HXeCCH, the H-Xe stretching frequency is reliably (by > 10 cm(-1)) higher in an Ar matrix than in a Kr matrix. In contrast, the H-Xe stretching frequency of HXeI in an Ar matrix is slightly lower than that in a Kr matrix. HXeH absorbs in Ar and Kr matrices at 1203.2 and 1192.1 cm(-1) (the stronger band for a Kr matrix), respectively. These bands are blue-shifted from the stronger band of HXeH in a Xe matrix (1166 cm(-1)) by 37 and 26 cm(-1), and this frequency order is the same as observed for HXeCl, HXeBr, and HXeCCH but different from HXeI. The present hybrid quantum-classical simulations successfully describe the main experimental findings. For HXeI in the < 110 > (double substitution) site, the order of the H-Xe stretching frequencies (nu(Xe) < nu(Ar) < nu(Kr)) is in accord with the experimental observations, and also the frequency shifts in Ar and Kr matrices from a Xe matrix are well predicted (30 and 34 cm(-1)). Both in the theory and experiment, the order of the H-Xe stretching frequencies differs from the case of HXeCl, which suggests the adequate theoretical description of the matrix effect. For HXeH in the < 100 > (single substitution) site, the order of the frequencies is nu(Xe) < nu(Kr) < nu(Ar), which also agrees with the experiments. The calculated frequency shifts for HXeH in Ar and Kr matrices with respect to a Xe matrix (36 and 23 cm(-1)) are in a good agreement with the experiments. The present calculations predict an increase of the H-Xe stretching frequencies in the noble-gas matrices with respect to vacuum. (C) 2015 AIP Publishing LLC.
  • Tsuge, M., Kalinowski, J., Gerber, R.B., Lee, Y.-P.
    Journal of Physical Chemistry A 119 (11) 2651 - 2660 1089-5639 2015 [Refereed][Not invited]
     
    Proton-bound rare-gas dimer (RgHRg)(+), in which Rg represents a rare-gas atom, serves as a prototypical system for proton solvation by inert-gas atoms. Until now, only centrosymmetric species with Rg = Ar, Kr, or Xe have been identified with infrared spectra. We employed electron bombardment during deposition of a mixture of Xe (or Kr) in p-H-2 at 3.2 K to prepare (RgHRg)(+). Lines at 847.0 and 972.1 cm(-1) are assigned as the Rg-H-Rg antisymmetric stretching (nu(3)) mode and its combination with the RgHRg symmetric stretching (nu(1) + nu(3)) mode of (XeHXe)(+) in solid p-H-2, respectively. Lines at 871.1 and 974.0 cm(-1) are assigned as the nu(3) and nu(1) + nu(3) modes of (KrHKr)(+) in solid p-H-2, respectively. Slightly shifted and broadened lines were observed for these species in solid n-H-2. These results agree satisfactorily with reported experimental values of (XeHXe)(+) and (KrHKr)(+) in solid Xe, Kr, and Ar, and with the quantum-chemically predicted anharmonic vibrational wavenumbers of these species in the gaseous phase; the significant spectral shifts in various matrixes are rationalized with the proton affinities of the hosts. When a mixture of Xe and Kr in p-H-2 was used, an additional broad feature at 1284 cm(-1) was observed and assigned as the nu(3) mode of (KrHXe)(+) in solid p-H-2. This line shifted to 1280 cm(-1) in solid n-H-2 and the corresponding line of (KrDXe)(+) was observed at 954 cm(-1) in n-D-2. The observations of these lines are new; the wavenumbers significantly blue shifted from those of the centrosymmetric (RgHRg)(+) agree with the quantum-chemically predicted anharmonic vibrational wavenumbers of 1279 cm(-1) for (KrHXe)(+) and 916 cm(-1) for (KrDXe)(+). Analysis of the computational results shows that electronic correlation effects play a much greater role for the asymmetric than for the symmetric species. An interpretation for this is provided.
  • Tsuge, M., Berski, S., R{\"a}s{\"a}nen, M., Latajka, Z., Khriachtchev, L.
    Journal of Chemical Physics 140 (4) 44323  0021-9606 2014/01/30 [Refereed][Not invited]
     
    The HXeY center dot center dot center dot H2O complexes (Y = Cl, Br, and I) are studied theoretically and experimentally. The calculations at the CCSD(T)/def2-TZVPPD level of theory predict two stable structures for Y = Cl and Br and one structure for Y = I, with interaction energies up to about -7 kcal mol(-1). In the experiments, we have identified several infrared absorption bands originating from the H-Xe stretching mode of these complexes in a xenon matrix. The monomer-to-complex frequency shifts of this mode are up to +82 cm(-1) (Y = Cl), +101 cm(-1) (Y = Br), and +138 cm(-1) (Y = I), i.e., the shift is smaller for more strongly bound molecules. Based on the agreement of the experimental and theoretical results, the observed bands are assigned to the most stable planar structure with an O-H center dot center dot center dot Y-Xe hydrogen bond. (C) 2014 AIP Publishing LLC.
  • Cohen, A., Tsuge, M., Khriachtchev, L., R{\"a}s{\"a}nen, M., Gerber, R.B.
    Chemical Physics Letters 594 18 - 22 0009-2614 2014/01/22 [Refereed][Not invited]
     
    HXeBr in CO2 and Xe environments is modeled at the B3LYP-D level of theory, using a full single shell of CO2 molecules and Xe atoms around the HXeBr molecule. For the CO2 environment, the optimized structure indicates a double substitutional site in the otherwise approximately preserved structure of solid CO2. The calculated vibrational spectra and energetic properties indicate strong interactions of HXeBr with the CO2 environment, which is significantly stronger than in the case of the Xe environment. The H-Xe stretching frequency obtained by a variant of the anharmonic VSCF method is in good accord with the available experimental data. (C) 2014 Elsevier B.V. All rights reserved.
  • TSUGE MASASHI
    分光研究 日本分光学会 62 (6) 268 - 275 0038-7002 2013/12/15 [Refereed][Invited]
  • Tsuge, M., Lignell, A., R{\"a}s{\"a}nen, M., Khriachtchev, L.
    Journal of Chemical Physics 139 (20) 204303  0021-9606 2013/11/22 [Refereed][Not invited]
     
    Noble-gas hydrides HNgY (Ng is a noble-gas atom and Y is an electronegative group) are sensitive probes of local environment due to their relatively weak bonding and large dipole moments. We experimentally studied HXeBr in Ar, Kr, and N-2 matrices, HXeCCH in Ne and N-2 matrices, and HXeH in an N-2 matrix. These are the first observations of noble-gas hydrides in an N-2 matrix. An N-2 matrix strongly increases the H-Xe stretching frequency of HXeBr and HXeCCH with respect to a Ne matrix, which is presumably due to a strong interaction between the HNgY dipole moment and quadrupole moments of the surrounding lattice N-2 molecules. The spectral shift of HXeBr in an N-2 matrix is similar to that in a CO2 matrix, which is a rather unexpected result because the quadrupole moment of CO2 is about three times as large as that of N-2. The H-Xe stretching frequencies of HXeBr and HXeCCH in noble-gas matrices show a trend of v(Ne) < v(Xe) < v(Kr) < v(Ar), which is a non-monotonous function of the dielectric constants of the noble-gas solids. The MP2(full) calculations of HXeBr and HXeCCH with the polarizable continuum model as well as the CCSD(T) calculations of the HXeBr . . . Ng and HXeCCH . . . Ng (Ng = Ne, Ar, Kr, and Xe) complexes cannot fully explain the experimental observations. It is concluded that more sophisticated computational models should be used to describe these experimental findings. (C) 2013 AIP Publishing LLC.
  • Tsuge, M., Tsuji, K., Kawai, A., Shibuya, K.
    Journal of Physical Chemistry A 117 (49) 13105 - 13111 1089-5639 2013/11/19 [Refereed][Not invited]
     
    The photochemistry of ozone water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O(D-1) + H2O -> H2O2 reaction was found to occur to form hydrogen peroxide, where the O(D-1) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone water complex, indicating that a neon matrix medium is most appropriate to study the Photochemistry of the ozone water complex.
  • Tsuge, M., Berski, S., R{\"a}s{\"a}nen, M., Latajka, Z., Khriachtchev, L.
    Journal of Chemical Physics 138 (10) 104314  0021-9606 2013/03/13 [Refereed][Not invited]
     
    The complexes of HXeI with hydrogen halides HY (Y = Br and I) are studied computationally and experimentally in a xenon matrix. The calculations at the CCSD(T)/def2-TZVPPD level of theory predict several energy minima for the HXeI center dot center dot center dot HY complexes with interaction energies from -4.69 to -0.23 kcal mol(-1). We have identified three bands of the HXeI center dot center dot center dot HI complexes in the H-Xe stretching region with the monomer-to-complex blue shifts from +37 to +96 cm(-1), and three bands of the HXeI center dot center dot center dot HBr complexes with blue shifts from +88 to +157 cm(-1). The structural assignments are done on the basis of the strong H-Xe and HY stretching bands and the decomposition rates upon broadband IR irradiation. The experimental bands with larger shifts are assigned to the most stable structures of the HXeI center dot center dot center dot HY complexes with the Y-H center dot center dot center dot I hydrogen bond. c 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794309]
  • Tsuge, M., Marushkevich, K., R{\"a}s{\"a}nen, M., Khriachtchev, L.
    Journal of Physical Chemistry A 116 (22) 5305 - 5311 1089-5639 2012/05/07 [Refereed][Not invited]
     
    The complexes of formic acid (HCOOH, FA) with carbon dioxide are studied by infrared spectroscopy in an argon matrix. Two trans-FA center dot center dot center dot CO2 and one cis-FA center dot center dot center dot CO2 complexes are experimentally identified while the calculations at the MP2(full)/6-311++G(2d,2p) level of theory predict one more minimum for the cis-FA center dot center dot center dot CO2 complex. The complex of the higher-energy conformer cis-FA with CO2 is prepared by vibrational excitation of the ground-state trans-FA conformer combined with thermal annealing. The lifetime of the cis-FA center dot center dot center dot CO2 complex in an argon matrix at 10 K is 2 orders of magnitude longer than that of the cis-FA monomer. This big difference is explained by the computational results which show a higher stabilization barrier for the complex. The solvation effects in solid argon are theoretically estimated and their contribution to the stabilization barriers of the higher-energy species is discussed. The relative barrier transmissions for hydrogen tunneling in the cis-FA center dot center dot center dot CO2 complex and cis-FA monomer are in good agreement with the experimental decay rates.
  • Tsuge, M., Berski, S., Stachowski, R., R{\"a}s{\"a}nen, M., Latajka, Z., Khriachtchev, L.
    Journal of Physical Chemistry A 116 (18) 4510 - 4517 1089-5639 2012/04/11 [Refereed][Not invited]
     
    We investigate the conditions when noble-gas hydrides can be found in real environments and report on the preparation and identification of the HXeBr center dot center dot center dot CO2 complex in a xenon matrix and HXeBr in a carbon dioxide matrix. The H-Xe stretching mode of the HXeBr center dot center dot center dot CO2 complex in a xenon matrix is observed at 1557 cm(-1), showing a spectral shift of +53 cm(-1) from the HXeBr monomer. The calculations at the CCSD(T)/aug-cc-pVTZ-PP(Xe,Br) level of theory give two stable structures for the HXeBr center dot center dot center dot CO2 complex with frequency shifts of +55 and +103 cm(-1), respectively. On the basis of the calculations, the experimentally observed band is assigned to the more stable structure with a "parallel" geometry. The HXeBr molecule was prepared in a carbon dioxide matrix and has the H-Xe stretching frequency of 1646 cm(-1), meaning a strong matrix shift and stabilization of the H-Xe bond. The deuterated species DXeBr in a carbon dioxide matrix absorbs at 1200 cm(-1). This is the first case where a noble-gas hydride is prepared in a molecular solid. The thermal stabilities of HXeBr and HXeBr center dot center dot center dot CO2 complex in a xenon matrix and HXeBr in a carbon dioxide matrix were examined. We have found a high thermal stability of HXeBr in carbon dioxide ice (at least up to 100 K), i.e., under conditions that may occur in nature.
  • Hoshina, K., Hagihara, H., Tsuge, M.
    Journal of Physical Chemistry A 116 (2) 826 - 831 1089-5639 2012 [Refereed][Not invited]
     
    Ionization and fragmentation of formic acid dimers (HCOOH)(2) and (DCOOD)(2) by irradiation of femtosecond laser pulses (100 fs, 800 nm, similar to 1 x 10(14) W/cm(2)) were investigated by time-of-flight (TOF) mass spectrometry. In the TOF spectra, we observed fragment ions (HCOOH)H+, (HCOOH)- HCOO+, and H3O+, which were produced via the dissociative ionization of (HCOOH)(2). In addition, we found that the TOF signals of COO+, HCOO+, and HCOOH+ have small but clear side peaks, indicating fragmentation with large kinetic energy release caused by Coulomb explosion. On the basis of the momentum matching among pairs of the side peaks, a Coulomb explosion pathway of the dimer dication, (HCOOH)(2)(2+) -> HCOOH+ + HCOOH+, was identified with the total kinetic energy release of 3.6 eV. Quantum chemical calculations for energies of (HCOOH)(2)(2+) were also performed, and the kinetic energy release of the metastable dication was estimated to be 3.40 eV, showing good agreement with the observation. COO+ and HCOO+ signals with kinetic energies of 1.4 eV were tentatively assigned to be fragment ions through Coulomb explosion occurring after the elimination of a hydrogen atom or molecule from (HCOOH)(2)(2+). The present observation demonstrated that the formic acid dimer could be doubly ionized prior to hydrogen bond breaking by intense femtosecond laser fields.
  • Hoshina, K., Kawamura, H., Tsuge, M., Tamiya, M., Ishiguro, M.
    Journal of Chemical Physics 134 (6) 64324  0021-9606 2011/02/14 [Refereed][Not invited]
     
    We investigated a formation channel of triatomic molecular hydrogen ions from ethane dication induced by irradiation of intense laser fields (800 nm, 100 fs, similar to 1 x 10(14) W/cm(2)) by using time of flight mass spectrometry. Hydrogen ion and molecular hydrogen ion (H,D)(n)+ (n = 1-3) ejected from ethane dications, produced by double ionization of three types of samples, CH(3)CH(3), CD(3)CD(3), and CH(3)CD(3), were measured. All fragments were found to comprise components with a kinetic energy of similar to 3.5 eV originating from a two-body Coulomb explosion of ethane dications. Based on the signal intensities and the anisotropy of the ejection direction with respect to the laser polarization direction, the branching ratios, H(+):D(+) = 66:34, H(2)(+):HD(+):D(2)(+) = 63:6:31, and H(3)(+):H(2)D(+): HD(2)(+):D(3)(+) = 26:31:34: 9 for the decomposition of C(2)H(3)D(3)(2+), were determined. The ratio of hydrogen molecules, H(2):HD:D(2) = 31:48:21, was also estimated from the signal intensities of the counter ion C(2)(H,D)(4)(2+). The similarity in the extent of H/D mixture in (H,D)(3)(+) with that of (H,D)(2) suggests that these two dissociation channels have a common precursor with the C(2)H(4)(2+)center dot center dot center dot H(2) complex structure, as proposed theoretically in the case of H3+ ejection from allene dication [A. M. Mebel and A. D. Bandrauk, J. Chem. Phys. 129, 224311 (2008)]. In contrast, the (H,D)(2)(+) ejection path with a lower extent of H/D mixture and a large anisotropy is expected to proceed essentially via a different path with a much rapid decomposition rate. For the Coulomb explosion path of C-C bond breaking, the yield ratios of two channels, CH(3)CD(3)(2+) -> CH(3)(+) + CD(3)(+) and CH(2)D(+) + CHD(2)(+), were 81:19 and 92:8 for the perpendicular and parallel directions, respectively. This indicates that the process occurs at a rapid rate, which is comparable to hydrogen migration through the C-C bond, resulting in smaller anisotropy for the latter channel that needs H/D exchange. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3549137]
  • Tsuge, M., Hoshina, K.
    International Journal of Mass Spectrometry 300 (1) 39 - 43 1387-3806 2011 [Refereed][Not invited]
     
    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) spectra for methyl esters H-X-OMe of 11 amino acid X were measured at various analyte/matrix mixing ratios using alpha-cyano-4-hydroxycinnamic acid (CHCA) matrix. For each amino acid, the effect of esterification on MALDI signals was examined by comparing the signal intensity ratio (H-X-OMe)H(+)/(CHCA)H(+) for the ester H-X-OMe with the comparable ratio XH(+)/(CHCA)H(+) for the corresponding amino acid X. For all 11 amino acids, the ratios for the esters are in line with a thermal equilibrium model [M. Tsuge, K. Hoshina, Investigation of protonation efficiency for amino acids in matrix-assisted laser desorption/ionization, Bull. Chem. Soc. Jpn. 83 (2010), 1188-1192.]. For 9 of the amino acids - Ala, Arg, Gly, Ile, Leu, Phe, Set. Trp, and Val - the ratio for the amino acid agrees with the ratio for the ester, within the standard error. For the other 2 amino acids - His and Lys - the ratio for the amino acid is exceptionally smaller than the ratio for the ester, indicating that the effect of esterification is significant. This compensation by esterification suggests that for His/CHCA and Lys/CHCA systems, the coexistence of a carboxyl group and a basic side chain are responsible for suppression in the formation of HisH(+) and LysH(+), possibly by reducing the amount of desorbed analyte and/or decreasing the effective gas-phase basicity (GB) in the MALDI plume. (C) 2010 Elsevier B.V. All rights reserved.
  • Tsuge, M., Hoshina, K.
    Bulletin of the Chemical Society of Japan 83 (10) 1188 - 1192 0009-2673 2010/10/05 [Refereed][Not invited]
     
    MALDI spectra for 20 natural amino acids were measured at various mixing ratios of amino acid (A) and matrix (M: CHCA or DHB) to clarify the main protonation process as well as MALDI plume conditions, which affect the detection sensitivity of analytes in MALDI. Signal intensities of protonated amino acids (AH(+)) relative to protonated matrix (MH+), obtained as AH(+)/MH+, revealed a clear correlation between AH(+)/MH+ and the gas-phase basicity (GB) of the respective amino acids except for three basic amino acids, Lys, His, and Arg. This relationship between AH(+)/MH+ and GB was interpreted in terms of a protonation model in which AH+ is produced through a reversible proton-transfer reaction of MH+ + A reversible arrow M + AH(+) reaching thermal equilibrium in the MALDI plume. The GB of matrix molecules and MALDI plume temperatures independently determined from analysis of the present data (851 kJ mol(-1) and 1510 K for CHCA and 830 kJ mol(-1) and 1330K for DHB) agreed well with values in the literature, indicating the validity of the present interpretation. The ratios AH(+)/MH+ for Lys, His, and Arg had lower values than those expected from the GB by a factor of 10(-1)-10(-2). This discrepancy could have been caused by proton acceptance by amino groups in amino acids, which are caused by an intramolecular hydrogen bond, determine the magnitude of the GB for basic amino acids.
  • K. Hoshina, M. Tsuge
    Chemical Physics Letters 489 (4-6) 154 - 158 0009-2614 2010/03/03 [Refereed][Not invited]
  • Shirota, T., Mano, N., Tsuge, M., Hoshina, K.
    Rapid Communications in Mass Spectrometry 24 (5) 679 - 686 0951-4198 2010/02/12 [Refereed][Not invited]
     
    The processes of H(3)O(+) production from alcohols (ethanol, 2-propanol, 1-propanol, 2-butanol) and ethers (diethyl ether and ethyl methyl ether), and their deuterium-substituted species, by intense laser fields (800 nm, 100 fs, similar to 1 x 10(14) W/cm) were investigated through time-of-flight (TOF) mass spectrometry. H(3)O(+) formation was observed for all these compounds except for ethyl methyl ether. From the analysis of TOF signals of H((3-n))D(n)O(+) (n = 0, 1, 2, and 3) that have expanding tails with increasing flight time, it has been confirmed that the reaction proceeds through metastable dissociation from the intermediate species C(2)H((5-m))D(m)O(+) (m = 0-5). The common shape of the H((3-n))D(n)O(+) signal profiles contains two major distributions in the time constant, i.e., fast and slow components of <50 ns and similar to 500 ns, respectively. The H((3-n))D(n)O(+) branching ratio is interpreted to be the result of complete scrambling of four hydrogen atoms at the C-C site in C(2)H(4)-OH(+), and partial exchange (18-38%) of a hydrogen atom in the OH group with four other hydrogen atoms within 1 ns prior to H((3-n))D(n)O(+) production. Ab initio calculations for the isomers and transition states Of C(2)H(5)O(+) were also performed, and the observed H((3-n))D(n)O(+) production mechanism has been discussed. In addition, a stable isomer having a complex structure and two isomerization pathways were discovered to contribute to the H(3)O(+) formation process. Copyright (C) 2010 John Wiley & Sons, Ltd.
  • Tsuge, M., Tsuji, K., Kawai, A., Shibuya, K.
    Journal of Physical Chemistry A 111 (18) 3540 - 3547 1089-5639 2007/04/19 [Refereed][Not invited]
     
    Matrix isolation infrared spectroscopy has been applied to study an ozone-water complex of atmospheric interest. The complex was identified in the spectral region of three normal modes of ozone and water. Ab initio calculation at MP4(SDQ), QCISD, and CCSD(T) levels indicates the existence of only one stable conformer, which accords with the present experimental result. This conformer belongs to the C-s symmetry group where two molecular planes of ozone and water are perpendicular to the C-s symmetry plane. The binding energy was calculated to be 1.89 kcal/mol at the CCSD(T)/6-311++G(3df,3pd)//CCSD(T)/6-311++G(d,p) level of theory. The formation constant and atmospheric abundance of the ozone-water complex are estimated using the thermodynamic and spectroscopic data obtained.
  • Tsuge, M., Hamatani, S., Kawai, A., Tsuji, K., Shibuya, K.
    Physical Chemistry Chemical Physics 8 (2) 256 - 263 1463-9076 2006 [Refereed][Not invited]
     
    The D-1-D-0 transitions of diphenylmethyl (DPM) and chlorodiphenylmethyl (CDPM) radicals were studied by laser induced fluorescence (LIF) spectroscopy in a supersonic jet. Laser induced fluorescence excitation and dispersed fluorescence (DF) spectra were obtained for DPM and CDPM radicals produced by ArF excimer laser (193 nm) photolyses of their chlorides. With the aid of the density functional theory (DFT) calculation, vibronic bands are assigned by comparing the observed LIF excitation spectra of the jet-cooled radicals with the single vibronic level DF spectra. Low-frequency vibrations of 55 and 53 cm(-1) in the ground and excited states, respectively, are assigned to the symmetric phenyl torsional mode of the DPM radical. The geometries of DPM in the ground and excited states are discussed with regards to observed spectra and DFT calculations. Similarly for the CDPM radical, symmetric phenyl torsional and Ph-C-Ph bending modes are assigned and the halogen-substitution effect in equilibrium geometry is discussed.

MISC

Books etc

  • Akira Kouchi, Takashi Shimonishi, Tomoya Yamazaki, Masashi Tsuge, Naoki Nakatani, Kenji Furuya, Hiromasa Niinomi, Yasuhiro Oba, Tetsuya Hama, Hiroyasu Katsuno, Naoki Watanabe, Yuki Kimura (Joint work)
    IntechOpen 2022/08
  • Masashi Tsuge, Yuan-Pern Lee (ContributorChapter 5 - Spectroscopy of molecules confined in solid para-hydrogen)
    Elsevier 2020/07 
    Solid para-hydrogen (p-H2) has emerged as a novel low-temperature matrix host with unique characteristics associated with a quantum solid. In this chapter, we introduce p-H2 matrix-isolation spectroscopy, presenting instrumentation and methods, the properties of solid p-H2, and varied spectral applications. For stable molecules, infrared spectra of methane at high resolution, propene, CH3OH and CH3F with internal rotation, molecular complexes with ortho-H2, and ultraviolet spectra of NO are discussed. The diminished cage effect allows the preparation of free radicals from photolysis in situ, either directly or via bimolecular reactions, such as Cl + unsaturated hydrocarbons to form radical products. Another novel method is the production of protonated and hydrogenated species on electron bombardment during deposition at 3.2 K. We have applied this method to small molecules (e.g., OCS), proton-bound dimers (e.g., N2-H+-N2) and polycyclic aromatic hydrocarbons that might be the carriers of unidentified infrared bands in astronomy. Hydrogen addition and abstraction reactions are also studied with photolytically produced H atoms from Cl + H2 (v = 1); several reactions with nitrogen-containing molecules (e.g., HONO and formamide) revealed reaction networks that are important for chemical evolution in space. Finally we present a future perspective on research using p-H2 matrix-isolation spectroscopy.

Presentations

Association Memberships

  • 原子衝突学会   JAPAN SOCIETY FOR MOLECULAR SCIENCE   日本分光学会   THE CHEMICAL SOCIETY OF JAPAN   

Research Projects

  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2024/04 -2027/03 
    Author : 柘植 雅士
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    Date (from‐to) : 2022/04 -2027/03 
    Author : 渡部 直樹, 柘植 雅士, Sameera W.M.C.
  • 氷の半導体的性質:n型半導体としての機能発現機構の定量的解明
    公益財団法人 クリタ水・環境科学振興財団：国内研究助成 特別テーマ 「水を究める」研究
    Date (from‐to) : 2024/10 -2025/09
  • 日本学術振興会：Grant-in-Aid for Transformative Research Areas (A)
    Date (from‐to) : 2023/04 -2025/03 
    Author : Masashi Tsuge
  • 公益財団法人 クリタ水・環境科学振興財団：国内研究助成
    Date (from‐to) : 2023/10 -2024/09
  • 日本学術振興会：科研費 基盤B
    Date (from‐to) : 2021/04 -2024/03 
    Author : 柘植雅士
  • JSPS：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2018/04 -2021/03 
    Author : Masashi Tsuge
     
    In the chemical evolution processes occurring within low temperature molecular clouds, it has been demonstrated that chemical reactions on icy grain surface play significant roles. However, chemical processes within ice mantle, which do not require photons and cosmic rays, have not been investigated. In this work, we aimed at revealing whether hydrogen atoms can penetrate into ice mantles or not. We found that hydrogen atoms penetrate into amorphous solid water and react with embedded atoms or molecules. The most important finding of this work is that hydrogen reactions occur above 20 K, where efficiency of surface hydrogen reactions is extremely low.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2008/04 -2011/03 
    Author : HOSHINA Kennosuke, TSUGE Masashi
     
    Fragmentation paths through fast hydrogen migration within ionized organic molecules by an intense femtosecond laser field were investigated based on measured ion yields and results of the quantum chemical calculation. The H_3O^+ ejection paths via C_2H_4OH^+ for ethers and alcohols, and via C_2H_5OH_2^+ for ethanol dimer, and their time scales were clarified. In the experiment using deuterium-labeled ethane, CH_3CD_3, it was demonstrated from H/D mixing ratios in the H_2^+,H_3^+,H_2 fragments that a reaction path through a CH_2CH_2^<2+>…H_2 complex produces H_2 and H_3^+ fragments.

Media Coverage

Academic Contribution

  • International committee member of Asian Workshop on Molecular Spectroscopy
    Date (from-to) :2024/03-Today
    Role: Planning etc
    Type: Academic society etc
  • Chemistry and Physics at Low Temperatures 2024
    Date (from-to) :2024/07/06-2024/07/11
    Role: Planning etc
    Type: Academic society etc
  • Date (from-to) :2023/11/05-2023/11/08
    Role: Planning etc
    Organizer, responsible person: Masashi Tsuge
  • The 6th Asian Workshop on Molecular Spectroscopy
    Date (from-to) :2022/11/02-2022/11/05
    Role: Planning etc
    Type: Competition etc

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