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Hidaka Hiroshi

Institute of Low Temperature Science　Frontier Ice and Snow ScienceAssistant Professor

Researcher basic information

■ Degree
  • 博士（理学）, 東京都立大学
  • 修士（理学）, 東京都立大学
■ URL
researchmap URLホームページURL■ Various IDs
J-Global ID■ Research Keywords and Fields
Research Keyword
  • 星間塵
  • 低温表面反応
  • REMPI
  • 水素分子
  • 反応熱
  • 星間化学
  • 惑星間空間
  • 重水素濃集
  • 低温
  • 原子反応
  • 地球外物質化学
  • 氷表面反応
  • 表面
  • アモルファス氷
  • トンネル反応
  • 極低温表面反応
  • 同位体分別
  • 星間分子
Research Field
  • Natural Science, Space and planetary sciences
  • Natural Science, Solid earth sciences
■ Educational Organization

Career

■ Career
Career
  • 2012
    Hokkaido University, Institute of Low Temperature Science, 助教
Educational Background
  • 2003, Tokyo Metropolitan University, Graduate School of Science, Department of Physics, Japan
  • 2003, Tokyo Metropolitan University, Graduate School, Division of Natural Science
  • 2000, Tokyo Metropolitan University, Graduate School of Science, Japan
  • 2000, Tokyo Metropolitan University, Graduate School, Division of Natural Science
  • 1998, Hosei University, 工学部, 機械工学科, Japan
  • 1998, Hosei University, Faculty of Engineering
Committee Memberships
  • 2012 - Present
    原子衝突学会, 運営委員, Society
  • 2009 - Present
    日本惑星科学会, 総務委員, Society

Research activity information

■ Papers
  • Methylamine Formation on Amorphous Solid Water via the Diffusive CH 3 + NH 2 Reaction as Investigated by the Cs + Ion Pickup Method
    Arisa Iguchi; Masashi Tsuge; Hiroshi Hidaka; Yasuhiro Oba; Naoki Watanabe
    ACS Earth and Space Chemistry, American Chemical Society (ACS), 20 Nov. 2025
    Scientific journal
  • Hydrogenation of HOCO and formation of interstellar CO2: A not so straightforward relation
    Germán Molpeceres; Joan Enrique-Romero; Atsuki Ishibashi; Yasuhiro Oba; Hiroshi Hidaka; Thanja Lamberts; Yuri Aikawa; Naoki Watanabe
    Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), 05 Mar. 2025
    Scientific journal, Abstract

    Carbon dioxide (CO2) is one of the most important interstellar molecules. While it is considered that it forms on the surface of interstellar dust grains, the exact contribution of different chemical mechanisms is still poorly constrained. Traditionally it is deemed that the CO + OH reaction occurring on top of ices is the main reaction path for its formation. Recent investigations showed that in reality the reaction presents a more complex mechanism, requiring an additional H-abstraction step. Building on our previous works, we carried out a detailed investigation of such H abstraction reactions with the hydrogen atom as a reactant for the abstraction reaction. We found an unconventional chemistry for this reaction, markedly depending on the isomeric form of the HOCO radical prior to reaction. The favored reactions are t-HOCO + H $\longrightarrow$ CO + H2O, c-HOCO + H $\longrightarrow$ CO2 + H2 and t/c-HOCO + H $\longrightarrow$ c/t-HCOOH. We estimate bounds for the rate constants of the less favored reaction channels, t-HOCO + H $\longrightarrow$ CO2 + H and c-HOCO + H $\longrightarrow$ CO + H2O, to be approximately 104 − 6 s−1. However, these estimates should be interpreted cautiously due to the significant role of quantum tunneling in these reactions and the complex electronic structure of the involved molecules, which complicates their study. Our findings underscore the need for detailed investigation into the chemistry of interstellar CO2 and pave the way for a reevaluation of its primary formation mechanisms in the interstellar medium.
  • Determination of the Branching Ratio of CH3OH + OH Reaction on Water Ice Surface at 10 K
    Atsuki Ishibashi; Hiroshi Hidaka; W. M. C. Sameera; Yasuhiro Oba; Naoki Watanabe
    The Astrophysical Journal, 01 Jan. 2024, [Peer-reviewed]
    Scientific journal
  • Methanol Formation through Reaction of Low-energy CH3 + Ions with an Amorphous Solid Water Surface at Low Temperature
    Y. Nakai; W. M. C. Sameera; K. Furuya; H. Hidaka; A. Ishibashi; N. Watanabe
    The Astrophysical Journal, 01 Aug. 2023
    Scientific journal
  • A systematic mechanistic survey on the reactions between OH radical and CH3OH on ice
    W. M. C. Sameera; Avon P. Jayaweera; Atsuki Ishibashi; Hiroshi Hidaka; Yasuhiro Oba; Naoki Watanabe
    Faraday Discussions, 245, 508, 518, Royal Society of Chemistry (RSC), 2023
    Scientific journal, Our systematic computational study suggests that the nature of the binding site or the reaction site has a significant effect on the computed binding energies or reaction barriers.
  • Direct Determination of the Activation Energy for Diffusion of OH Radicals on Water Ice
    A. Miyazaki; M. Tsuge; H. Hidaka; Y. Nakai; N. Watanabe
    The Astrophysical Journal Letters, 940, 1, L2, L2, American Astronomical Society, 14 Nov. 2022, [Peer-reviewed]
    Scientific journal, 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.
  • Modelling the Radical Chemistry on Ice Surfaces: An Integrated Quantum Chemical and Experimental Approach
    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, Frontiers Media SA, 30 May 2022
    Scientific journal, 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.
  • UV-Induced Formation of Ice XI Observed Using an Ultra-High Vacuum Cryogenic Transmission Electron Microscope and its Implications for Planetary Science
    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, Frontiers Media SA, 08 Dec. 2021
    Scientific journal, 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.
  • Efficient Formation Pathway of Methyl Formate: The Role of OH Radicals on Ice Dust
    A. Ishibashi; H. Hidaka; Y. Oba; A. Kouchi; N. Watanabe
    The Astrophysical Journal Letters, 01 Nov. 2021, [Peer-reviewed]
    Scientific journal
  • Transmission Electron Microscopy Study of the Morphology of Ices Composed of H2O, CO2, and CO on Refractory Grains
    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, American Astronomical Society, 01 Sep. 2021, [Peer-reviewed]
    English, Scientific journal
  • CH3O Radical Binding on Hexagonal Water Ice and Amorphous Solid Water
    W. M. C. Sameera; Bethmini Senevirathne; Stefan Andersson; Muhsen Al-lbadi; Hiroshi Hidaka; Akira Kouchi; Gunnar Nyman; Naoki Watanabe
    The Journal of Physical Chemistry A, 125, 1, 387, 393, American Chemical Society (ACS), 14 Jan. 2021, [Peer-reviewed]
    English, Scientific journal
  • Delivery of Electrons by Proton-Hole Transfer in Ice at 10 K: Role of Surface OH Radicals
    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, American Chemical Society (ACS), 14 Jan. 2021, [Peer-reviewed]
    English, Scientific journal
  • Photostimulated desorption of OH radicals from amorphous solid water: Evidence for the interaction of visible light with an OH-ice complex
    A. Miyazaki; N. Watanabe; W. M. C. Sameera; Y. Nakai; M. Tsuge; T. Hama; H. Hidaka; A. Kouchi
    Physical Review A, 102, 5, American Physical Society (APS), 20 Nov. 2020, [Peer-reviewed]
    English, Scientific journal
  • Diffusive Hydrogenation Reactions of CO Embedded in Amorphous Solid Water at Elevated Temperatures ∼70 K
    Masashi Tsuge; Hiroshi Hidaka; Akira Kouchi; Naoki Watanabe
    The Astrophysical Journal, 900, 2, 187, 187, American Astronomical Society, 15 Sep. 2020, [Peer-reviewed]
    English, Scientific journal
  • Formation experiments of organic molecules by catalytic reactions in low-temperature and low-pressure environments
    Yuki Kimura; Rikako Sato; AkiraTsuchiyama; YusukeTamenori; Tetsuya Hama; Hiroshi Hidaka; Naoki Watanabe; Akira Kouchi; Hiroko Nagahara
    Low Temperature Science, 78, 79, 90, Mar. 2020, [Peer-reviewed]
  • Ultraviolet-photon exposure stimulates negative current conductivity in amorphous ice below 50 K
    N. Watanabe; W. M. C. Sameera; H. Hidaka; A. Miyazaki; A. Kouchi
    Chemical Physics Letters, 737, 136820, 2019, [Peer-reviewed]
    English, Scientific journal
  • 超高真空極低温透過型電子顕微鏡の開発─氷のその場観察をめざして─
    香内晃; 日高宏; 羽馬哲也; 木村勇気; 渡部直樹; 中坪俊一; 藤田和之; 新堀邦夫; 池田正幸
    日本雪氷学会誌 雪氷, in press, 2018, [Peer-reviewed]
    Scientific journal
  • Liquid-like behavior of UV-irradiated interstellar ice analog at low temperatures.
    Shogo Tachibana; Akira Kouchi; Tetsuya Hama; Yasuhiro Oba; Laurette Piani; Iyo Sugawara; Yukiko Endo; Hiroshi Hidaka; Yuki Kimura; Ken-Ichiro Murata; Hisayoshi Yurimoto; Naoki Watanabe
    Science advances, 3, 9, eaao2538, Sep. 2017, [Peer-reviewed], [International Magazine]
    English, Scientific journal, Interstellar ice is believed to be a cradle of complex organic compounds, commonly found within icy comets and interstellar clouds, in association with ultraviolet (UV) irradiation and subsequent warming. We found that UV-irradiated amorphous ices composed of H2O, CH3OH, and NH3 and of pure H2O behave like liquids over the temperature ranges of 65 to 150 kelvin and 50 to 140 kelvin, respectively. This low-viscosity liquid-like ice may enhance the formation of organic compounds including prebiotic molecules and the accretion of icy dust to form icy planetesimals under certain interstellar conditions.
  • Simulations and spectra of water in CO matrices
    Rafael Escribano; Emilio Artacho; Akira Kouchi; Tetusya Hama; Yuki Kimura; Hiroshi Hidaka; Naoki Watanabe
    PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19, 10, 7280, 7287, Mar. 2017, [Peer-reviewed]
    English, Scientific journal
  • Hydrogenation and Deuteration of C2H2 and C2H4 on Cold Grains: A Clue to the Formation Mechanism of C2H6 with Astronomical Interest
    Hitomi Kobayashi; Hiroshi Hidaka; Thanja Lamberts; Tetsuya Hama; Hideyo Kawakita; Johannes Kaestner; Naoki Watanabe
    ASTROPHYSICAL JOURNAL, 837, 2, 155, 169, Mar. 2017, [Peer-reviewed]
    English, Scientific journal
  • Matrix sublimation method for the formation of high-density amorphous ice
    A. Kouchi; T. Hama; Y. Kimura; H. Hidaka; R. Escribano; N. Watanabe
    CHEMICAL PHYSICS LETTERS, 658, 287, 292, Aug. 2016, [Peer-reviewed]
    English, Scientific journal
  • Stepwise formation of H3O+(H2O)(n) in an ion drift tube: Empirical effective temperature of association/dissociation reaction equilibrium in an electric field
    Yoichi Nakai; Hiroshi Hidaka; Naoki Watanabe; Takao M. Kojima
    JOURNAL OF CHEMICAL PHYSICS, 144, 22, 224306, Jun. 2016, [Peer-reviewed]
    English, Scientific journal
  • 21pBG-3 Reaction equilibria for stepwise formation of H_3O(H_2O)_n^+ cluster ions in an electric field of an ion drift tube
    Nakai Yoichi; Hidaka Hiroshi; Watanabe Naoki; Kojima Takao M.
    Meeting Abstracts of the Physical Society of Japan, 70, 632, 632, The Physical Society of Japan (JPS), 2015
    Japanese
  • Formation of deuterated formaldehyde on low temperature surfaces: isotope effect of quantum tunneling reactions
    H. Hidaka; M. Watanabe; A. Kouchi; N. Watanabe
    FIRST INTERNATIONAL CONFERENCE ON CHEMICAL EVOLUTION OF STAR FORMING REGION AND ORIGIN OF LIFE (ASTROCHEM2012), 1543, 318, 325, 2013, [Peer-reviewed]
    English, International conference proceedings
  • Water formation through a quantum tunneling surface reaction, OH + H 2, at 10K
    Y. Oba; N. Watanabe; T. Hama; K. Kuwahata; H. Hidaka; A. Kouchi
    Astrophysical Journal, 749, 1, 67, 78, Institute of Physics Publishing, 10 Apr. 2012, [Peer-reviewed]
    English, Scientific journal
  • 星間分子雲での微粒子表面における水素の化学物理過程
    渡部直樹; 香内晃; 羽馬哲也; 日高宏; 大場康弘; 千貝健
    表面科学, 33, 12, 662, 668, 2012
    Japanese, Scientific journal
  • FTIR study of ammonia formation via the successive hydrogenation of N atoms trapped in a solid N_2 matrix at low temperatures
    HIDAKA H.
    Physical Chemistry Chemical Physics, 13, 35, 15798, 15802, 2011, [Peer-reviewed]
    English, Scientific journal
  • Formation of ammonia molecules by H addition reactions to N atom on interstellar grain surfaces at low temperatures
    Hidaka Hiroshi; Kouchi Akira; Watanabe Naoki
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 292, 292, GEOCHEMICAL SOCIETY OF JAPAN, 2011
    分子雲でアンモニア分子が生成される過程として提案されている，低温星間塵表面における窒素原子への水素原子付加反応の検証を実験的手法により行った．実験は，超高真空槽内に設置した低温基板（10K）にNおよびH原子を照射し，赤外吸収分光により生成分子の観測を行った．その結果，10Kという低温表面でも上記表面反応によりアンモニアが生成されることが明らかになった．
  • Formation of H2O Ice through the Surface Reaction O2 + H at Low Temperatures: Reaction Kinetics and Structure of the Ice
    Oba, Y; Miyauchi, N; Chigai, T; Hidaka, H; Watanabe, N; Kouchi, A
    Physics and Chemistry of Ice 2010, eds. Y. Furukawa, G. Sazaki, T. Uchida, N. Watanabe, Hokkaido University Press, Sapporo, ISBN: 978-4-8329-0361-6, 361, 368, 2011
    English
  • Sequential hydrogenation of molecular oxygen on cold surfaces: reaction kinetics and structure of formed H2O ice
    Y.Oba; N.Miyauchi; H.Hidaka; T.Chigai; N.Watanabe; A.Kouchi
    Proceedings of the International Astronomical Union, 280, 2011, [Peer-reviewed]
    English, International conference proceedings
  • Formation of amorphous H2O ice from the reactions of cold H atoms with solid O2 at 10 K
    A. Kouchi; N. Watanabe; H. Hidaka; N. Miyauchi; Y. Oba; T. Chigai
    Astron. Soc. Pacific Conf. Ser., 414, 338, 346, 2010, [Peer-reviewed]
    English, Scientific journal
  • Physicochemical processes of atomic hydrogen on amorphous solid water at very low temperatures
    Watanabe Naoki; Kouchi Akira; Hidaka Hiroshi; Kimura Yuki; Hama Tetsuya
    Abstracts of Papers of the American Chemical Society, 239, 2010, [Peer-reviewed]
  • Hydrogen isotope exchange and H(D) atom addition reaction of solid formaldehyde on amorphous solid water at low temperatures
    Hiroshi Hidaka; Motohiro Watanabe; Akira Kouchi; Naoki Watanabe
    Journal of Physics: Conference Series, 194, 13, 132024, Institute of Physics Publishing, 24 Dec. 2009
    English, International conference proceedings
  • REACTION ROUTES IN THE CO-H2CO-d(n)-CH3OH-d(m) SYSTEM CLARIFIED FROM H(D) EXPOSURE OF SOLID FORMALDEHYDE AT LOW TEMPERATURES
    H. Hidaka; M. Watanabe; A. Kouchi; N. Watanabe
    ASTROPHYSICAL JOURNAL, 702, 1, 291, 300, Sep. 2009, [Peer-reviewed]
    English, Scientific journal
  • FORMATION OF COMPACT AMORPHOUS H2O ICE BY CODEPOSITION OF HYDROGEN ATOMS WITH OXYGEN MOLECULES ON GRAIN SURFACES
    Y. Oba; N. Miyauchi; H. Hidaka; T. Chigai; N. Watanabe; A. Kouchi
    ASTROPHYSICAL JOURNAL, 701, 1, 464, 470, Aug. 2009, [Peer-reviewed]
    English, Scientific journal
  • Hydrogen isotope exchange and H(D) atom addition reaction of solid formaldehyde on amorphous solid water at low temperatures
    H. Hidaka; M. Watanabe; A. Kouchi; N. Watanabe
    Journal of physics: Conference series, 194, 132024, 2009, [Peer-reviewed]
    English, Scientific journal
  • Formation of CO2 molecules by a surface reaction CO+OH at low temperatures.
    OBA Yasuhiro; WATANABE Naoki; HIDAKA Hiroshi; KOUCHI Akira; PIRRONELLO Varelio
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 56, 66, 66, GEOCHEMICAL SOCIETY OF JAPAN, 2009
    二酸化炭素は分子雲中星間塵アイスマントルの主要な構成成分であるが、気相反応によってその存在量を説明することができないため、その生成には塵表面での反応が重要だと考えられている。これまでの研究では、UVなどの外部エネルギーをH2OやCOなどを含む混合氷に照射してCO2生成が確認されてきたが、外部エネルギー無しにCO2が生成するかどうかは明らかにされていなかった。本講演では、100Kに冷却されたOHラジカルとCOの固体表面上での反応でCO2生成が確認されたので、その結果について報告する。
  • Formation of water molecule by surface atomic reactions on interstellar grains at low temperatures
    OBA Yasuhiro; MIYAUCHI Naoya; CHIGAI Takeshi; HIDAKA Hiroshi; WATANABE Naoki; KOUCHI Akira
    Chikyukagaku, 43, 4, 117, 131, The Geochemical Society of Japan, 2009, [Peer-reviewed]
    Japanese, Scientific journal, Formation of water by reaction of oxygen molecules (O2) with hydrogen atoms (H) were investigated at low temperatures (10-40 K) in order to reveal the possible reaction pathways to yield water on grain surfaces in molecular clouds. Two types of experiments for surface reaction between O2 and H were performed: one of which was that solid O2 was deposited onto the surface, followed by H irradiations to the O2, another of which was that gaseous O2 was continuously codeposited with H onto the surface and was reacted with each other. H2O (D2O) and H2O2 (D2O2) were quickly produced through successive reactions of O2 with H (D). Reaction kinetics and isotope effect are discussed for the former experiment. For the latter experiment, the dependence of compositions of the products on the temperature and O2/H ratio, and also the structure of the H2O ice produced are examined.
  • Nonenergetic reactions between atomic hydrogen and molecules on interstellar grain surfaces
    N. Watanabe; A. Kouchi; H. Hidaka; Y. Oba; N. Miyauchi
    Journal of Physics: Conference Series, 194, 1, 012044, Institute of Physics Publishing, 2009, [Peer-reviewed]
    English, International conference proceedings
  • 1. Formation of interstellar ice by low temperature surface atomic reactions
    A. Kouchi; Y. Oba; N. Miyauchi; H. Hidaka; N. Watanabe
    Cryobiology, 59, 3, 370, Elsevier {BV}, 2009, [Peer-reviewed]
  • 332 極低温表面原子反応O2+Hによる水分子生成 : アモルファス氷の触媒効果(原始惑星系円盤II,オーラルセッション11)
    大場 康弘; 宮内 直弥; 千貝 健; 日高 宏; 渡部 直樹; 香内 晃
    日本惑星科学会秋期講演会予稿集, 2008, 0, 93, 93, 日本惑星科学会, Nov. 2008
    Japanese, Scientific journal
  • Structural effects of ice grain surfaces on the hydrogenation of CO at low temperatures
    H. Hidaka; N. Miyauchi; A. Kouchi; N. Watanabe
    Chemical Physics Letters, 456, 1-3, 36, 40, 21 Apr. 2008, [Peer-reviewed]
    English, Scientific journal
  • Formation of hydrogen peroxide and water from the reaction of cold hydrogen atoms with solid oxygen at 10 K
    N. Miyauchi; H. Hidaka; T. Chigai; A. Nagaoka; N. Watanabe; A. Kouchi
    CHEMICAL PHYSICS LETTERS, 456, 1-3, 27, 30, Apr. 2008, [Peer-reviewed]
    English, Scientific journal
  • Formation of water from surface-atomic reactions at low temperatures
    OBA YASUHIRO; MIYAUCHI NAOYA; CHIGAI TAKESHI; HIDAKA HIROSHI; WATANABE NAOKI; KOUCHI AKIRA
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 55, 371, 371, GEOCHEMICAL SOCIETY OF JAPAN, 2008
    水分子は星間塵アイスマントル中で最も多く存在する分子であるが、その生成メカニズムはいまだはっきりしない。本研究では星間塵上表面原子反応による水分子生成反応の検証を行った。酸素分子を10Kに冷却された基板上に蒸着させ、そこに水素分子をプラズマ解離させて生成する水素原子を照射した。水素原子照射により酸素分子へ水素原子が付加され、過酸化水素、水の生成が確認された。これは酸素分子への水素原子逐次付加反応O2+H->HO2、HO2+H->H2O2、H2O2+H->H2O+OHが起こったことによる。
  • 分子雲で生じる低温表面反応：表面実験で探る分子進化
    日高宏; 渡部直樹; 香内晃
    低温科学, 66, 13, 2008, [Peer-reviewed]
    Japanese, Scientific journal
  • Interstellar amorphous ice ggrain: The role in chemical evolution
    Naoki Watanabe; Akira Kouchi; Orie Mouri; Akihiro Nagaoka; Hiroshi Hidaka
    Shinku/Journal of the Vacuum Society of Japan, 50, 4, 282, 290, 2007, [Peer-reviewed]
    Japanese, Scientific journal
  • Temperature, composition, and hydrogen isotope effect in the hydrogenation of CO on amorphous ice surface at 10-20 K
    H. Hidaka; A. Kouchi; N. Watanabe
    Journal of Chemical Physics, 126, 20, 204707, 2007, [Peer-reviewed]
    English, Scientific journal
  • Dependence of the effective rate constants for the hydrogenation of CO on the temperature and composition of the surface
    N. Watanabe; A. Nagaoka; H. Hidaka; T. Shiraki; T. Chigai; A. Kouchi
    PLANETARY AND SPACE SCIENCE, 54, 11, 1107, 1114, Sep. 2006, [Peer-reviewed]
    English, Scientific journal
  • 星間塵表面での低温水素原子反応による分子進化
    渡部直樹; 長岡明宏; 日高宏; 香内晃
    固体物理 特集号 ＜新しい水素の科学＞, 41, 1, 59, 68, 2006, [Peer-reviewed]
    Japanese, Scientific journal
  • 星間塵表面での低温水素原子反応による分子進化
    渡部直樹; 長岡明宏; 日高宏; 香内晃
    固体物理11, 41, 755, 764, 2006, [Peer-reviewed]
    Japanese, Scientific journal
  • Relative reaction rates of hydrogenation and deuteration of solid CO at very low temperatures
    Naoki Watanabe; Hiroshi Hidaka; Akira Kouchi
    AIP Conference Proceedings, 855, 122, 127, 2006, [Peer-reviewed]
    English, International conference proceedings
  • Deuterium fractionation in the reactions of D + H2CO and H + D2CO at 15 K
    Hiroshi Hidaka; Naoki Watanabe; Akira Kouchi
    AIP Conference Proceedings, 855, 107, 112, 2006, [Peer-reviewed]
    English, International conference proceedings
  • D-enrichment in molecular clouds: H-D substitution in solid methanol
    Nagaoka Akihiro; Watanabe Naoki; Hidaka Hiroshi; Kouchi Akira
    Abstracts for Annual Meeting of the Mineralogical Society of Japan, 2005, 136, 136, Japan Association of Mineralogical Sciences, 2005
    Deuterium enrichment of interstellar methanol is reproduced experimentally for the first time via grain-surface H-D substitution in solid methanol at 10 K. The mechanism proposed here represents a key route for D-enrichment that reproduces the high observed abundances of deuterated methanol (D/H ratio of up to 0.4, compared to the cosmic ratio of about 10-5), including multiple deuterations.
  • 星間塵表面反応による星間分子の重水素濃集メカニズム
    渡部直樹; 長岡明宏; 日高宏; 香内晃
    日本惑星科学会誌, 14, 175, 182, 2005, [Peer-reviewed]
    Japanese, Scientific journal
  • Conversion of H2CO to CH3OH by reactions of cold atomic hydrogen on ice surfaces below 20 K
    H Hidaka; N Watanabe; T Shiraki; A Nagaoka; A Kouchi
    ASTROPHYSICAL JOURNAL, 614, 2, 1124, 1131, Oct. 2004, [Peer-reviewed]
    English, Scientific journal
  • 星間塵表面反応による有機分子生成および重水素濃集機構
    渡部直樹; 香内晃; 白木隆裕; 長岡明宏; 日高宏
    日本惑星科学会誌, 13, 226, 232, 2004, [Peer-reviewed]
    Japanese, Scientific journal
  • Influence of ice composition on the formation on interstellar formaldehyde and methanol on dust grains
    A. Nagaoka; N. Watanabe; T. Shiraki; H. Hidaka; A. Kouchi
    Proceedings of the 37th isas luna and planetary symposium, 4, 91, 94, 2004, [Peer-reviewed]
    English, International conference proceedings
  • Mobility of NO+ in helium gas at 77 and 4.3 K
    H Hidaka; S Jinno; H Tanuma; N Kobayashi
    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 36, 8, 1515, 1524, Apr. 2003, [Peer-reviewed]
    English, Scientific journal
  • Molecular ion mobility in helium gas at very low temperature
    H. Hidaka; S. Matoba; S. Jinno; H. Tanuma; N. Kobayashi
    Atomic collision research in japan -Progress report-, 28, 28, 18, 19, 2002, [Peer-reviewed]
    English
  • Swarm study of Kr2+ ions in helium gas at very low temperature
    H Tanuma; H Hidaka; N Kobayashi
    PHYSICS OF ELECTRONIC AND ATOMIC COLLISIONS, 500, 699, 703, 2000, [Peer-reviewed]
    English, International conference proceedings
■ Other Activities and Achievements
■ Lectures, oral presentations, etc.
  • Reactive desorption of methanol from amorphous solid water at 10K
    HIDAKA Hiroshi
    Cosmic dust 2019, 14 Aug. 2019, English, Invited oral presentation
    [Invited], [International presentation]
  • Tunneling chamical reactions on low-temperature interstellar grain surfaces
    日髙 宏
    One-day symposium on E-ring based molecular science, 07 Feb. 2013, English, Invited oral presentation
    [Invited], [International presentation]
  • Formation of deuterated formaldehyde on low temperature surface: isotope effect of quantum tunneling reactions
    日髙 宏
    ASTROCHEM2012, 2012, English, Invited oral presentation
    [Invited], [International presentation]
  • Formation routes of deuterated formaldehyde and methanol by tunneling reaction on amorphous solid water at 10-20K
    日髙 宏
    COSPAR2012, 2012, English, Invited oral presentation
    [Invited], [International presentation]
  • 低温氷表面での水素原子反応における氷構造の影響-アモルファスと結晶の比較-
    日髙 宏
    水素量子アトミクス 第6回研究会, 13 Dec. 2007, Invited oral presentation
    [Invited], [Domestic Conference]
■ Affiliated academic society
  • 日本惑星科学会
  • 原子衝突研究協会
  • 日本物理学会
  • The Japanese Society for Planetary Sciences
  • The Societry for Atomic Collision Research
  • The Physical Society of Japan
■ Research Themes
  • Molecular-scale elucidation of the reaction elementary processes on the model dust surfaces by single-molecule surface spectroscopy
    Grants-in-Aid for Scientific Research
    19 Nov. 2020 - 31 Mar. 2025
    今田 裕; 杉本 宜昭; 清水 智子; 金 有洙; 数間 恵弥子; 日高 宏; 香内 晃
    本研究では3つの研究項目（1. 塵モデル表面の作製・評価、2. 氷形成過程と構造の分子・原子レベル解明、3. 表面反応素過程の単一分子レベル解明）に分けられる。項目1では、塵表面のモデルシステムとなるケイ酸塩薄膜はパルスレーザー堆積法（PLD）装置の立上げを最初に行った。次に、チタン酸ストロンチウム(STO)基板にルテニウム酸ストロンチウム薄膜を堆積し、その構造をX線回折、原子間力顕微鏡および走査型トンネル顕微鏡を用いて評価した。PLDにおける各種パラメータに加え、STO基板の洗浄方法を最適化することでSRO薄膜の欠陥を減らせることが明らかとなった。項目2では、アモルファス氷(a-H2O)上のCO、CO2の表面拡散の活性化エネルギー(Esd)を測定した。COの場合は、porousなa-H2O上の方がcompact なa-H2O上よりもEsdが大きいことも分かった。a-H2O上に生成されるCO結晶が、a-H2Oを一様に覆うのではなく、１個のCO単結晶がa-H2Oに付着するような形態で成長することを見出した。さらに、結晶氷表面を微視的に理解することは、氷表面上の様々な化学反応を理解する重要なステップであることから、様々な基板を用いて結晶氷を作製して原子間力顕微鏡によって、その構造を原子レベルで解析した。Pt(111)およびRh(111)基板上に作成した氷は、膜厚によって積層の仕方が異なるが、表面構造は膜厚に依らず同じであった。理想表面は得られず、短距離的秩序を持つ構造が共通に得られ、定説を覆す結果となった。項目3では、星間分子の単分子反応としてAOCSを対象とし、塵モデル表面の対照実験として、Ag表面の上の吸着状態を走査トンネル顕微鏡(STM)により調べた。Ag表面上でOCSは島状構造を形成する一方、孤立分子は観察されず、紫外光または電子によってOCSが反応した様子を確認した。
    Japan Society for the Promotion of Science, Grant-in-Aid for Transformative Research Areas (A), Institute of Physical and Chemical Research, 20H05849
  • 高感度・非破壊・表面吸着分子分析装置の開発で開拓するラジカル反応研究
    Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Pioneering)
    Jul. 2021 - Mar. 2024
    日高 宏
    本研究課題は，分子雲から原始惑星系円盤に至る天体の進化にともなって生じる，様々な有機分子の生成過程を解明するため，氷星間塵表面で生じるラジカル分子が関与する化学反応の実験研究を可能にする，高感度非破壊表面吸着分子分析装置の開発を行うことである．本分析技術の確立は，固体表面に吸着した微量分子が関与する様々な科学課題に対しても，実験による新たな研究可能領域の開拓に寄与するものである．
    本装置の開発はCsイオンピックアップ法を基に，①反跳イオンの捕集効率の向上，②捕集イオンの質量分析後の異性体分離機構を導入するという方針で行う．初年度となる本年度は，まず，反跳イオンを捕集するレンズシステムの改良および，イオンが反跳する基板に対する，捕集レンズシステムの設置確度を調整できる真空槽の設計・製作を行った．これにより，現在使用している試作捕集レンズおよび設置角度が固定されている真空槽というセットアップと比較して，微量な反跳イオンをより少ない損失で質量分析エリアに導入することが可能になる．
    さらに，異性体分離をするために導入予定であった，イオンファネルと移動管質量分析器の組み合わせによる分析システムの有効性の検討を行った．その結果，有限なリソースの中で幅広い種類の異性体の分離を行うには移動管法は適していない可能性があることが分かった．よって，異性体分離法の代替案として，イオントラップとレーザーを用いた冷イオン振動前期解離分光法を採用することとし，最適なイオントラップ形状決定のため，線径トラップ型イオントラップのイオン軌道シミュレーションを開始した．
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Pioneering), Hokkaido University, 21K18153
  • Elucidation of ion-surface reactions on a interstellar dust surface: exploring their unknown roles in molecular evolution
    Grants-in-Aid for Scientific Research
    01 Apr. 2018 - 31 Mar. 2021
    Nakai Yoichi
    We have performed experimental studies of the reactions between low-energy molecular ions and the surface of interstellar dust ice, for which there was little experimental information. For this purpose, we have developed an experimental apparatus using a reactive scattered ion mass spectrometry (RIS), which is more sensitive than the conventional detection methods for chemical species existing on the surface. The method was improved so that the advantage of RIS could be utilized for chemical species on the low-temperature ice surface. As a result, we have achieved high detection sensitivity for chemical species on low-temperature ice surface. The reaction products were observed after irradiating the surface of the ice thin film formed on the cooled metal substrate with low-energy CH3+ ions. We obtained experimental results indicating the formation of methanol molecules due to the irradiation of the CH3+ ions to the ice surface.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Institute of Physical and Chemical Research, 18H01273
  • 分子雲における氷・有機物生成
    文部科学省: 科学研究補助金(新学術領域研究(研究領域提案型))
    Jun. 2013 - Mar. 2018
    香内 晃
    Competitive research funding
  • 星間塵表面での分子進化と新しい同位体分別機構
    文部科学省: 科学研究補助金(基盤研究(S))
    May 2012 - Mar. 2017
    渡部 直樹
    Competitive research funding
  • Quantitative investigation for ion-induced nucleation under non-equilibrium conditions of association/dissociation reactions: experimental approaches for elementary formation processes
    Grants-in-Aid for Scientific Research
    01 Apr. 2013 - 31 Mar. 2016
    NAKAI Yoichi; WATANABE Naoki; KOJIMA Takao; HIDAKA Hiroshi
    We performed stable and precise measurements compared with previous studies for Gibbs free energy changes of stepwise association reactions of a water molecule to H3O+(H2O)n ions using a ion drift tube with a selected ion injection. Furthermore, an empirical effective temperature of the reaction equilibrium constants was obtained for association/dissociation reactions of a water molecule to/from H3O+(H2O)n ions in a pure water vapor. The effective temperature means a representative physical quantity of collision energy influenced by an electric field. It was found that a new parameter describing electric field dependence of the effective temperature presumably reflects structures of H3O+(H2O)n ions. We also performed R&D of ion handling methods in an RF ion trap, such as an ion mass selection, in order to make use of RF ion traps for cluster formation experiments.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Institute of Physical and Chemical Research, 25287148
  • 極低温原子間力顕微鏡によるアモルファス氷の表面構造および表面電位の解明
    文部科学省: 科学研究補助金(基盤研究(C))
    May 2014 - Mar. 2016
    日髙 宏
    Principal investigator, Competitive research funding
  • 氷生成過程のその場観察・構造解析のための極低温超高真空透過型電子顕微鏡の開発
    文部科学省: 科学研究補助金(基盤研究(A))
    Oct. 2013 - Mar. 2016
    香内 晃
    Competitive research funding
  • Quantitative elucidation for ion induced nucleation in the atmosphere: Approach through the experiments for elementary processes
    Grants-in-Aid for Scientific Research
    01 Apr. 2010 - 31 Mar. 2013
    NAKAI Yoichi; WATANABE Naoki; KOJIMA Takao; HIDAKA Hiroshi
    Experimental study for cluster ion formation, early stages of ion induced nucleation, has been performed. We developed the experimental equipment, in which the region for production of initial ions is separated from that for generation of cluster ions, in order to define the reaction paths. Gibbs free energy changes for the stepwise association of an H2O molecule were measured for H3O+(H2O)n cluster ions and our method has provided more stable and precise results compared with previous measurements. In the use of initial NO+ ions, we have reduced influence of metastable NO+ ions in produced initial ions, using hydrogen buffer gas.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), The Institute of Physical and Chemical Research, 22540498
  • Elucidation of the mechanism of deuterium enrichment for ammonia molecule on the interstellar grain surface and use the enrichment fraction for temperature estimation of molecular clouds
    Grants-in-Aid for Scientific Research
    2012 - 2012
    HIDAKA Hiroshi
    ECR (Electron Cyclotron Resonance) nitrogen atomic source using microwave frequency 2.45GHz has been developed for use in the experimental study of the ortho-para ratio and the degree of deuterium enrichment of ammonia molecule which formed on the interstellar grain surface by the atom-atom addition reactions in molecular clouds. Magnetic field configuration for the plasma confinement was designed by 3D magnetostatic analysis, in order to achieve the nitrogen atomic source with the high flux and the high dissociation fraction.
    Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Competitive research funding, 24740362
  • Observation of surface structure of amorphous ice and role of amorphous ice in surface atomic reactions at low temperatures
    Grants-in-Aid for Scientific Research
    2010 - 2012
    KOUCHI Akira; WATANABE Naoki; HIDAKA Hiroshi
    An ultrahigh vacuum low temperature atomic force microscope for in-situ deposition of amorphous ice and for observation of ice surface has been developed. We have succeeded to observe the surface structure of amorphous ice and found that the surface of amorphous ice is very porous. This might cause the catalytic properties of amorphous ice in surface atomic reactions.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Competitive research funding, 22340157
  • Ice surface processes: tunneling reactions and isotope fractionation
    Grants-in-Aid for Scientific Research
    2009 - 2011
    WATANABE Naoki; HIDAKA Hiroshi
    Ice surface reactions relevant to chemical evolution and deuterium fractionation were experimentally investigated. Activation energies for ice-surface diffusion of H and D atoms were determined. It was found that effective mass of reaction system is a control-factor of tunneling reactions. The reactivities of tunneling reactions related to deuterium fraction of formaldehyde can be well explained by the effective masses. A novel route of CO_2 formation on the ice surface was found.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Innovative Areas (Research a proposed research project), Hokkaido University, Competitive research funding, 21200048
  • Deuterium fractionation of water molecule via grain surface reactions at very low temperatures
    Grants-in-Aid for Scientific Research
    2009 - 2011
    WATANABE Naoki; HIDAKA Hiroshi
    Water molecule formation and its deuterium fractionation via surface tunneling reactions were investigated experimentally, relevant to chemical evolution in a molecular cloud. We found that H_2O molecule is produced by tunneling reaction, OH + H_2, at very low temperature surfaces and that, from the isotope effect on the above reaction, the formation of OD is essential for deuterium fractionation of water rather than HD or D_2 formation.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Competitive research funding, 21540502
  • Study for the energy partition process in H2 formation by the H-H recombination on interstellar grain surface
    Grants-in-Aid for Scientific Research(若手研究(B))
    2007 - 2008
    Hiroshi HIDAKA
    極低温星間塵表面上で生成・脱離した水素分子の反応熱分配過程を実験的に明らかにするため,低温基板表面で水素原子の結合反応により水素分子を生成し,脱離した水素分子の運動・振動・回転エネルギー分布を測定する実験装置を構築した.
    Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Competitive research funding, 19740301
  • Role of cosmic-grain surface reactions in the deuterium fractionationof interstellar molecules
    Grants-in-Aid for Scientific Research(基盤研究(B))
    2007 - 2008
    Naoki WATANABE; HIROSHI HIDAKA
    星間分子の重水素濃集プロセスとして研究代表者らが提唱している極低温星間塵表面反応を, 実験により定量的に評価した. 特に, 高度な重水素濃集が観測で確認されているホルムアルデヒド, メタノールの重水素化表面反応に焦点をあて, 重要な反応経路について実効的な反応速度定数を決定し, 上記分子種に関する重水素濃集の星間塵表面反応ネットワークを完成させた.
    Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Competitive research funding, 19340167