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Quantification of OH radical formation in solar UV photolysis of nonanoic acid

Research Project

Project/Area Number 22K18019
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 63010:Environmental dynamic analysis-related
Research InstitutionUniversity of Tsukuba (2023)
The University of Tokyo (2022)

Principal Investigator

Numadate Naoki  筑波大学, 数理物質系, 助教 (20850100)

Project Period (FY) 2022-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2023: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2022: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Keywords大気化学 / 液体ノナン酸 / 界面 / 光分解 / レーザー誘起蛍光 / 吸収断面積 / 不純物 / ノナン酸 / 光化学反応断面積 / 紫外吸収分光 / 気液界面 / 光化学反応 / 脱離生成物 / レーザー誘起蛍光法 / 光反応断面積 / 液体有機物 / 光反応
Outline of Research at the Start

空気と界面活性な有機分子の気液界面における化学反応は地球の気候変動を理解する上で重要な要素である。近年、太陽紫外線を吸収しないと考えられてきた有機物が、エアロゾルなどの気液界面に存在する場合には光反応を起こす可能性が示唆された。本研究ではレーザー誘起蛍光法を用いて、液体有機物(ノナン酸) の界面における光反応、特にOHラジカル生成過程の定量測定法を確立することを目的とする。また、太陽紫外線を含む波長領域(215-330 nm) においてOHラジカル生成効率を定量することで、気液界面の光反応という新たなOH生成過程が大気化学へ及ぼす影響を検証する。

Outline of Final Research Achievements

We developed a new laser apparatus for UV laser photolysis of liquid organic surface and succeeded in direct observation and quantitative measurement of gaseous OH radical formation in the 213 nm photolysis of neat nonanoic acid (NA) using laser-induced fluorescence. Using vibrational sum-frequency generation spectroscopy, we revealed the cyclic dimer structure of the NA molecules at the liquid surface which can inhibit the OH radical formation. We also developed a device for recrystallization at low temperatures and under anaerobic conditions and measured UV absorption cross section of the extremely purified NA. The obtained cross sections at the wavelengths longer than 260 nm are much smaller than that before purification by recrystallization. This result indicates that the previously reported absorption data of wavelengths longer than 260 nm by liquid NA originates from trace impurities such as ketones and keto acids intrinsically contained in NA reagent.

Academic Significance and Societal Importance of the Research Achievements

本研究課題によって、液体有機物界面の光化学反応性の絶対値を定量する実験手法が開発された。これにより現在の大気モデルにおいて最大の不確定性とされている気液界面の光化学反応研究に一定の道筋がつけられた。加えて、近年の大気化学分野において注目されているノナン酸の光分解反応によるOHラジカル生成過程が従来の定説とは異なりほぼ無視できることが明らかにされ、液体試薬を扱った光化学研究における微量不純物の影響力を強く認識させることとなった。これらの研究成果は大気化学分野の室内実験研究において極めて重要な技術と知見であり、今後の気候変動予測の精度向上に貢献することが期待される。

Report

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

    (18 results)

All 2024 2023 2022

All Journal Article (3 results) (of which Peer Reviewed: 3 results,  Open Access: 1 results) Presentation (15 results) (of which Int'l Joint Research: 8 results,  Invited: 1 results)

  • [Journal Article] 液体ノナン酸界面の紫外光分解に伴うOHラジカル脱離過程の直接観測と定量測定2024

    • Author(s)
      沼舘直樹, 齊藤翔大, 羽馬哲也
    • Journal Title

      分光研究

      Volume: 1

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Impurity contribution to ultraviolet absorption of saturated fatty acids2023

    • Author(s)
      Saito Shota、Numadate Naoki、Teraoka Hidemasa、Enami Shinichi、Kobayashi Hirokazu、Hama Tetsuya
    • Journal Title

      Science Advances

      Volume: 9 Issue: 38

    • DOI

      10.1126/sciadv.adj6438

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Direct Observation and Quantitative Measurement of OH Radical Desorption During the Ultraviolet Photolysis of Liquid Nonanoic Acid2022

    • Author(s)
      Naoki Numadate, Shota Saito, Yuki Nojima, Taka-aki Ishibashi, Shinichi Enami, and Tetsuya Hama
    • Journal Title

      The Journal of Physical Chemistry Letters

      Volume: 13 Issue: 35 Pages: 8290-8297

    • DOI

      10.1021/acs.jpclett.2c02199

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Presentation] 液体有機物の紫外吸収スペクトル測定にかかる不純物の寄与2024

    • Author(s)
      齊藤翔大, 沼舘直樹, 寺岡秀将, 江波進一, 小林広和, 羽馬哲也
    • Organizer
      次世代アストロケミストリー:素過程理解に基づく学理の再構築 第4回 領域全体集会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 液体有機物界面における光分解反応の定量2023

    • Author(s)
      沼舘直樹, 齊藤翔大, 野嶋優妃, 石橋孝章, 江波進一, 羽馬哲也
    • Organizer
      原子衝突学会第48回年会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 液体有機物界面の光分解ダイナミクス研究への挑戦2023

    • Author(s)
      沼舘直樹, 小泉憲生, 齊藤翔大, 羽馬哲也
    • Organizer
      原子衝突学会第48回年会
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] 羽馬哲也, 齊藤翔大, 沼舘直樹, 寺岡秀将, 小林広和, 江波進一2023

    • Author(s)
      不純物を除去した液相脂肪酸の紫外吸収スペクトルと吸収断面積
    • Organizer
      原子衝突学会第48回年会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 齊藤翔大, 沼舘直樹, 寺岡秀将, 小林広和, 江波進一, 羽馬哲也2023

    • Author(s)
      液体脂肪酸の光吸収断面積と対流圏での光分解速度
    • Organizer
      第28回大気化学討論会(2023)
    • Related Report
      2023 Annual Research Report
  • [Presentation] Impurity contribution to photoabsorption of saturated fatty acids and its implications to tropospheric chemistry2023

    • Author(s)
      Tetsuya Hama, Shota Saito, Naoki Numadate, Hidemasa Teraoka, Shinichi Enami, Hirokazu Kobayashi
    • Organizer
      Workshop on Interstellar Matter 2023 (ISM2023)
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Ultraviolet absorption of liquid nonanoic acid and its implications to atmospheric chemistry2023

    • Author(s)
      Tetsuya Hama, Shota Saito, Naoki Numadate, Hidemasa Teraoka, Shinichi Enami, Hirokazu Kobayashi
    • Organizer
      The 7th Asian Workshop on Molecular Spectroscopy
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 液体脂肪酸試薬中に含まれる微量不純物が紫外吸収スペクトルに与える影響2023

    • Author(s)
      齊藤翔大, 沼舘直樹, 寺岡秀将, 小林広和, 江波進一, 羽馬哲也
    • Organizer
      第17回分子科学討論会
    • Related Report
      2023 Annual Research Report
  • [Presentation] Absolute cross section for OH radical desorption during the 213 nm photolysis of liquid nonanoic acid2023

    • Author(s)
      Naoki NUMADATE, Shota SAITO, Yuki NOJIMA, Taka-aki ISHIBASHI, Shinichi ENAMI, Tetsuya HAMA
    • Organizer
      38th Symposium on Chemical Kinetics and Dynamics
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Dynamics study on ultraviolet photodissociation of liquid oleic acid using laser-induced fluorescence2023

    • Author(s)
      Kensei KOIZUMI, Shota SAITO, Naoki NUMADATE, Tetsuya HAMA
    • Organizer
      38th Symposium on Chemical Kinetics and Dynamics
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Purification of liquid carboxylic acids by recrystallization method and measurement of absorption spectra in near UV wavelength2023

    • Author(s)
      Shota SAITO, Hidemasa TERAOKA, Naoki NUMADATE, Tetsuya HAMA
    • Organizer
      38th Symposium on Chemical Kinetics and Dynamics
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 液体ノナン酸の光反応におけるOHラジカル生成の定量2022

    • Author(s)
      沼舘直樹, 齊藤翔大, 野嶋優妃, 石橋孝章, 江波 進一, 羽馬哲也
    • Organizer
      第16回分子科学討論会
    • Related Report
      2022 Research-status Report
  • [Presentation] Absorption cross section, fluorescence, and photodissociation of liquid carboxylic acids at 213 and 266 nm2022

    • Author(s)
      SAITO, Shota, NUMADATE, Naoki, HAMA, Tetsuya
    • Organizer
      37th Symposium on Chemical Kinetics and Dynamics
    • Related Report
      2022 Research-status Report
    • Int'l Joint Research
  • [Presentation] Direct detection of OH radicals in the photolysis of liquid nonanoic acid using laser-induced fluorescence2022

    • Author(s)
      S. Saito, N. Numadate, Y. Nojima, T. Ishibashi, S. Enami, T. Hama
    • Organizer
      The 6th Asian Workshop on Molecular Spectroscopy
    • Related Report
      2022 Research-status Report
    • Int'l Joint Research
  • [Presentation] Quantification of photodesorption of OH following the photolysis of liquid organics2022

    • Author(s)
      S. Saito, N. Numadate, Y. Nojima, T. Ishibashi, S. Enami, T. Hama
    • Organizer
      Symposium on Next Generation Astrochemistry
    • Related Report
      2022 Research-status Report
    • Int'l Joint Research

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Published: 2022-04-19   Modified: 2025-01-30  

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