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Theoretical study of physicochemical process for water photolysis and radiolysis

Research Project

Project/Area Number 22K04993
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 31010:Nuclear engineering-related
Research InstitutionJapan Atomic Energy Agency

Principal Investigator

Takeshi Kai  国立研究開発法人日本原子力研究開発機構, 原子力科学研究所 原子力基礎工学研究センター, 研究主幹 (70403037)

Project Period (FY) 2022-04-01 – 2025-03-31
Project Status Completed (Fiscal Year 2024)
Budget Amount *help
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2024: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2023: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2022: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Keywords放射線工学・ビーム科学 / 光分解・放射線分解 / DNA損傷 / 水の光分解・放射線分解 / モンテカルロコード
Outline of Research at the Start

水の光分解・放射線分解に関する基礎研究は、生命科学や原子力科学における新たな知見となる。その過程は、物理・物理化学・化学過程に分類される。その中でも特に、化学活性種の初期生成に相当する物理化学過程は、実験・シミュレーション共に非常に困難であり、多くの未解明メカニズムが存在する。本研究では、物理化学過程に特化した計算コードを高度化することで、ラジカルの初期生成メカニズムを解明し、得られた結果を化学過程に接続することで、水分解の全貌解明を目指す。この基礎科学における新展開は、自然科学におけるブレークスルーとなり、水分解が関与する生命科学・原子力科学のみならず様々な分野のイノベーションに貢献する。

Outline of Final Research Achievements

Cutting-edge basic research on photolysis and radiolysis of water will provide new insights into radiation DNA damage and other processes in the life sciences. The processes are classified into physical, physicochemical, and chemical processes. Physicochemical processes, which correspond to the initial formation of chemically active species, are extremely difficult to study both experimentally and by simulation, and there are many unexplained mechanisms. This study aim to elucidate the initial formation mechanism of the species by the computational code specialized for physicochemical processes, and to connect the obtained results to chemical processes in order to elucidate the whole picture of water radiolysis. This new development in basic science will be a breakthrough in life science and contribute to innovation in various fields as well as in life science and nuclear science where water splitting is involved.

Academic Significance and Societal Importance of the Research Achievements

気相中の孤立した水分子は、電子状態が量子化されているため、付与エネルギーが決定すると、生成されるラジカルの種類は一意に定まる。しかし、これらのデータからは、液相水の化学実験の結果を再現することはできない。つまり、液相特有の分子集団的効果により、イオン化閾値以下のエネルギー付与でも、励起したり電離したりすると考えられる。本研究課題では「水に光や放射線を照射すると、どのようなメカニズムで励起と電離が共存するのか?」を問う。この基本原理は、放射線科学・光科学における残された難問の一つである。その成果は水分解が関与する生命科学・原子力科学のみならず様々な分野のイノベーションに貢献する。

Report

(4 results)
  • 2024 Annual Research Report   Final Research Report ( PDF )
  • 2023 Research-status Report
  • 2022 Research-status Report
  • Research Products

    (17 results)

All 2025 2024 2023 2022

All Journal Article (16 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 16 results,  Open Access: 6 results) Presentation (1 results) (of which Invited: 1 results)

  • [Journal Article] Computational analysis of the spatial distributions of low-energy electrons generated via water photolysis and photoinjection into electrodes in water2025

    • Author(s)
      Kai Takeshi、Toigawa Tomohiro、Matsuya Yusuke、Hirata Yuho、Tsuchida Hidetsugu、Yokoya Akinari
    • Journal Title

      The Journal of Chemical Physics

      Volume: 162 Issue: 15

    • DOI

      10.1063/5.0252783

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Multiple DNA damages induced by water radiolysis demonstrated using a dynamic Monte Carlo code2025

    • Author(s)
      Kai Takeshi、Toigawa Tomohiro、Matsuya Yusuke、Hirata Yuho、Tsuchida Hidetsugu、Ito Yuma、Yokoya Akinari
    • Journal Title

      Communications Chemistry

      Volume: 8 Issue: 1 Pages: 60-60

    • DOI

      10.1038/s42004-025-01453-x

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Development of a chemical code applicable to ions based on the PHITS code for efficient and visual radiolysis simulations2025

    • Author(s)
      Matsuya Yusuke、Yoshii Yuji、Kusumoto Tamon、Ogawa Tatsuhiko、Ohnishi Seiki、Hirata Yuho、Sato Tatsuhiko、Kai Takeshi
    • Journal Title

      Physical Chemistry Chemical Physics

      Volume: 27 Issue: 14 Pages: 6887-6898

    • DOI

      10.1039/d4cp04216f

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Significant role of secondary electrons in the formation of a multi-body chemical species spur produced by water radiolysis2024

    • Author(s)
      Kai Takeshi、Toigawa Tomohiro、Matsuya Yusuke、Hirata Yuho、Tezuka Tomoya、Tsuchida Hidetsugu、Yokoya Akinari
    • Journal Title

      Scientific Reports

      Volume: 14 Issue: 1 Pages: 24722-24722

    • DOI

      10.1038/s41598-024-76481-z

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Consideration of the dielectric response for radiation chemistry simulations2024

    • Author(s)
      Toigawa Tomohiro、Kai Takeshi、Kumagai Yuta、Yokoya Akinari
    • Journal Title

      The Journal of Chemical Physics

      Volume: 160 Issue: 21

    • DOI

      10.1063/5.0211089

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Liquid water radiolysis induced by secondary electrons generated from MeV-energy carbon ions2024

    • Author(s)
      Tsuchida Hidetsugu、Tezuka Tomoya、Kai Takeshi、Matsuya Yusuke、Majima Takuya、Saito Manabu
    • Journal Title

      The Journal of Chemical Physics

      Volume: 161 Issue: 10 Pages: 104503-104503

    • DOI

      10.1063/5.0227465

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed
  • [Journal Article] A step-by-step simulation code for estimating yields of water radiolysis species based on electron track-structure mode in the PHITS code2024

    • Author(s)
      Matsuya Yusuke、Yoshii Yuji、Kusumoto Tamon、Akamatsu Ken、Hirata Yuho、Sato Tatsuhiko、Kai Takeshi
    • Journal Title

      Physics in Medicine & Biology

      Volume: 69 Issue: 3 Pages: 035005-035005

    • DOI

      10.1088/1361-6560/ad199b

    • Related Report
      2023 Research-status Report
    • Peer Reviewed
  • [Journal Article] Development of a model for evaluating the luminescence intensity of phosphors based on the PHITS track-structure simulation2024

    • Author(s)
      Hirata Yuho、Kai Takeshi、Ogawa Tatsuhiko、Matsuya Yusuke、Sato Tatsuhiko
    • Journal Title

      Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

      Volume: 547 Pages: 165183-165183

    • DOI

      10.1016/j.nimb.2023.165183

    • Related Report
      2023 Research-status Report
    • Peer Reviewed
  • [Journal Article] Changes in molecular conformation and electronic structure of DNA under 12C ions based on first-principles calculations2024

    • Author(s)
      Sekikawa Takuya、Matsuya Yusuke、Hwang Beomju、Ishizaka Masato、Kawai Hiroyuki、?no Yoshiaki、Sato Tatsuhiko、Kai Takeshi
    • Journal Title

      Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

      Volume: 548 Pages: 165231-165231

    • DOI

      10.1016/j.nimb.2023.165231

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Nature of the physicochemical process in water photolysis uncovered by a computer simulation2023

    • Author(s)
      Kai Takeshi、Toigawa Tomohiro、Ukai Masatoshi、Fujii Kentaro、Watanabe Ritsuko、Yokoya Akinari
    • Journal Title

      The Journal of Chemical Physics

      Volume: 158 Issue: 16 Pages: 164103-164103

    • DOI

      10.1063/5.0149333

    • Related Report
      2023 Research-status Report
    • Peer Reviewed
  • [Journal Article] First-principles simulation of an ejected electron produced by monochromatic deposition energy to water at the femtosecond order2023

    • Author(s)
      Kai Takeshi、Toigawa Tomohiro、Matsuya Yusuke、Hirata Yuho、Tezuka Tomoya、Tsuchida Hidetsugu、Yokoya Akinari
    • Journal Title

      RSC Advances

      Volume: 13 Issue: 46 Pages: 32371-32380

    • DOI

      10.1039/d3ra05075k

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Improvement of the hybrid approach between Monte Carlo simulation and analytical function for calculating microdosimetric probability densities in macroscopic matter2023

    • Author(s)
      Sato Tatsuhiko、Matsuya Yusuke、Ogawa Tatsuhiko、Kai Takeshi、Hirata Yuho、Tsuda Shuichi、Parisi Alessio
    • Journal Title

      Physics in Medicine & Biology

      Volume: 68 Issue: 15 Pages: 155005-155005

    • DOI

      10.1088/1361-6560/ace14c

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Development of an electron track-structure mode for arbitrary semiconductor materials in PHITS2023

    • Author(s)
      Hirata Yuho、Kai Takeshi、Ogawa Tatsuhiko、Matsuya Yusuke、Sato Tatsuhiko
    • Journal Title

      Japanese Journal of Applied Physics

      Volume: 62 Issue: 10 Pages: 106001-106001

    • DOI

      10.35848/1347-4065/ad00f4

    • Related Report
      2023 Research-status Report
    • Peer Reviewed
  • [Journal Article] Initial yield of hydrated electron production from water radiolysis based on first-principles calculation2023

    • Author(s)
      Takeshi Kai, Tomohiro Toigawa, Yusuke Matsuya, Yuho Hirata, Tomoya Tezuka, Hidetsugu Tsuchida, Akinari Yokoya
    • Journal Title

      Royal Society of Chemistry Advances

      Volume: 13 Issue: 11 Pages: 7076-7086

    • DOI

      10.1039/d2ra07274b

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] An Analytical Method for Quantifying the Yields of DNA Double-Strand Breaks Coupled with Strand Breaks by γ-H2AX Focus Formation Assay Based on Track-Structure Simulation2023

    • Author(s)
      Yachi Yoshie、Matsuya Yusuke、Yoshii Yuji、Fukunaga Hisanori、Date Hiroyuki、Kai Takeshi
    • Journal Title

      International Journal of Molecular Sciences

      Volume: 24 Issue: 2 Pages: 1386-1386

    • DOI

      10.3390/ijms24021386

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Impact of the Lorentz force on electron track structure and early DNA damage yields in magnetic resonance-guided radiotherapy2022

    • Author(s)
      Yachi Yoshie、Kai Takeshi、Matsuya Yusuke、Hirata Yuho、Yoshii Yuji、Date Hiroyuki
    • Journal Title

      Scientific Reports

      Volume: 12 Issue: 1 Pages: 16412-16412

    • DOI

      10.1038/s41598-022-18138-3

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] 放射線生物影響の最初期過程に関する計算機シミュレーション ―DNA損傷の直接効果と間接効果―2023

    • Author(s)
      甲斐健師
    • Organizer
      第3回日本量子医科学会学術大会
    • Related Report
      2023 Research-status Report
    • Invited

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Published: 2022-04-19   Modified: 2026-01-16  

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