過渡分子種を超高感度・超高速で検出する分光法の開拓

• Project/Area Number: 20K20365
• Project/Area Number (Other): 18H05351 (2018-2019)
• Research Category: Grant-in-Aid for Challenging Research (Pioneering)
• Allocation Type: Multi-year Fund (2020); Single-year Grants (2018-2019)
• Review Section: Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
• Research Institution: Gakushuin University
• Principal Investigator: 岩田 耕一 学習院大学, 理学部, 教授 (90232678)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥26,000,000 (Direct Cost: ¥20,000,000、Indirect Cost: ¥6,000,000); Fiscal Year 2021: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000); Fiscal Year 2020: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000); Fiscal Year 2019: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2018: ¥16,640,000 (Direct Cost: ¥12,800,000、Indirect Cost: ¥3,840,000)
• Keywords: ラマン分光法 / 時間分解測定 / 化学反応

Outline of Research at the Start

本研究では，ピコ秒時間分解ラマン分光法と表面増強ラマン散乱(SERS)分光法を融合させた「ピコ秒時間分解表面増強ラマン分光法」を開発して，化学反応中間体などの過渡分子種を超高感度・超高速で検出することをめざす．この「ピコ秒時間分解表面増強ラマン分光法」では，金や銀などの金属ナノ粒子の表面近傍に存在する分子のラマン散乱が表面プラズモン共鳴および金属への電荷移動遷移への共鳴によって著しく増大することを利用する．化学反応の理解は，化学における主要な研究課題の一つである．本研究が所期の目的を達すれば，化学反応の理解を著しく進歩させるための実験手段を提供できることになる．

Outline of Annual Research Achievements

本研究課題の目的は，化学反応の中間体となる短寿命分子種を高感度に検出するための超高速分光法を開発することである．この目的のためにはまず高安定なピコ秒時間分解ラマン分光計を製作することが必要となる．研究代表者らは，安定性に優れたフェムト秒レーザーを光源に利用することで高安定ピコ秒時間分解ラマン分光計を製作することに成功した．この分光計ではノッチフィルターでフェムト秒光パルスを狭帯域化してピコ秒光パルスに変換している．出力安定性は二乗平均平方根0.8％であり，周波数・時間積はフーリエ変換限界の1.2から1.3倍であった．この新たな方式によるピコ秒時間分解ラマン分光計の開発を報告した論文は国際学術誌で高い評価を受けて，カバー論文に選ばれた．
新たに製作した高安定ピコ秒時間ラマン分解計を利用して，金および銀のナノ粒子近傍におけるターチオフェン分子の最低励起1重項状態における振動緩和過程を観測した．この実験で，電子励起されたターチオフェンと金属ナノ粒子との間の3ピコ秒以内での高速な振動エネルギー移動が振動モード特異的に進行することを観測した．この実験結果に基づいて，分子内および分子間の振動カップリングによるエネルギー伝達モデルを提案することができた．光照射によって生成したターチオフェンラジカルカチオンの時間分解ラマンスペクトルの測定から，金属ナノ粒子によるモード選択的な振動位相緩和の加速やねじれ構造の緩和を示唆した．一連の研究は，分子内および分子間の振動相互作用に誘起されたエネルギー伝達機構を提案する重要な意味を持っている．
最終年度である令和5年度には，研究実績について論文を執筆するとともに，国際会議で5回の招待講演を含む6回の研究発表を行った．これらの機会を利用して世界各地の専門家と議論して研究成果について多面的な理解を深めるとともに，本課題の成果を広く発信した．

Research Products

• [Journal Article] Energy Transfer Characteristics of Lipid Bilayer Membranes of Liposomes Examined with Picosecond Time-Resolved Raman Spectroscopy (2023)
  • Author(s): Nojima Yuki、Takaya Tomohisa、Iwata Koichi
  • Journal Title: The Journal of Physical Chemistry B Volume: 127 Issue: 30 Pages: 6684-6693
  • DOI: 10.1021/acs.jpcb.3c02120
  • Peer Reviewed
• [Journal Article] Conformational Relaxation Dynamics of Poly(3-hexylthiophene) Photoexcited in Solution as Studied by Femtosecond Time-Resolved Stimulated Raman Spectroscopy in 1190-1550 nm Region (2023)
  • Author(s): Tomohisa Takaya, Koichi Iwata
  • Journal Title: The Journal of Physical Chemistry B Volume: 127 Issue: 34 Pages: 7542-7552
  • DOI: 10.1021/acs.jpcb.3c02118
  • Peer Reviewed
• [Journal Article] Photoionization of 3-Methylindole Embedded in Sodium Dodecyl Sulfate and Dodecyltrimethylammonium Chloride Micelles: Migration of Electrons Generated in Micelle Cores and Their Solvation in Outside Water (2023)
  • Author(s): Goryo Shion, Iwata Koichi
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 14 Issue: 6 Pages: 1479-1484
  • DOI: 10.1021/acs.jpclett.2c03799
  • Peer Reviewed
• [Journal Article] Torsional relaxation dynamics of vinylene groups in photoexcited MEH-PPV as studied by time-resolved resonance stimulated Raman spectroscopy in the 900-1500 nm region (2022)
  • Author(s): Tomohisa Takaya, Masanori Shinohara, Koichi Iwata
  • Journal Title: Chemical Physics Letters Volume: 802 Pages: 139779-139779
  • DOI: 10.1016/j.cplett.2022.139779
  • Peer Reviewed
• [Journal Article] Dynamics of electron ejection on photoionization of trans-stilbene and biphenyl in acetonitrile as observed with femtosecond time-resolved near-IR absorption spectroscopy (2022)
  • Author(s): Mizuho Kajita, Tomohisa, Takaya, Koichi Iwata
  • Journal Title: Physical Chemistry Chemical Physics Volume: 24 Issue: 9 Pages: 5411-5418
  • DOI: 10.1039/d1cp05533j
  • Peer Reviewed
• [Journal Article] Development of a highly stable picosecond time-resolved Raman spectrometer with a femtosecond light source (2021)
  • Author(s): Tsukasa Tokita, Tomohisa Takaya, Koichi Iwata
  • Journal Title: Journal of Raman Spectroscopy Volume: 52 Issue: 12 Pages: 2051-2057
  • DOI: 10.1002/jrs.6232
  • Peer Reviewed
• [Journal Article] Laser Flash Photolysis Studies on Radical Monofluoromethylation by (Diarylamino)naphthalene Photoredox Catalysis: Long Lifetime of the Excited State is Not Always a Requisite (2020)
  • Author(s): Noto Naoki、Takahashi Keigo、Goryo Shion、Takakado Akira、Iwata Koichi、Koike Takashi、Akita Munetaka
  • Journal Title: The Journal of Organic Chemistry Volume: 85 Issue: 20 Pages: 13220-13227
  • DOI: 10.1021/acs.joc.0c01999
  • Peer Reviewed
• [Journal Article] Near-infrared resonance stimulated Raman study of short-lived transients in PTB7 films (2020)
  • Author(s): Takaya Tomohisa、Enokida Ippei、Furukawa Yukio、Iwata Koichi
  • Journal Title: Vibrational Spectroscopy Volume: 106 Pages: 103011-103011
  • DOI: 10.1016/j.vibspec.2019.103011
  • Peer Reviewed / Open Access
• [Journal Article] Supramolecular fluorescence sensor for liquefied petroleum gas (2019)
  • Author(s): Zhan Yi-Yang、Liao Jingyuan、Kajita Mizuho、Kojima Tatsuo、Takahashi Satoshi、Takaya Tomohisa、Iwata Koichi、Hiraoka Shuichi
  • Journal Title: Communications Chemistry Volume: 2 Issue: 1
  • DOI: 10.1038/s42004-019-0212-6
  • Peer Reviewed / Open Access
• [Journal Article] Structure and Dynamics of Charge Carriers Photogenerated in Pristine and Blended Poly(3-hexylthiophene) Films: Direct Observation by Femtosecond Time-Resolved Near-IR Inverse Raman Spectroscopy (2019)
  • Author(s): Tomohisa Takaya, Ippei Enokida, Yukio Furukawa, Koichi Iwata
  • Journal Title: Molecules Volume: 24 Issue: 3 Pages: 431-431
  • DOI: 10.3390/molecules24030431
  • Peer Reviewed / Open Access
• [Journal Article] Ultrafast Electron Solvation in Room Temperature Ionic Liquid Observed by Femtosecond Time-Resolved Near-IR Spectroscopy (2019)
  • Author(s): Manping Ye, Koichi Iwata
  • Journal Title: Chem. Lett. Volume: 48 Issue: 5 Pages: 422-425
  • DOI: 10.1246/cl.181043
  • NAID: 130007642577
  • Peer Reviewed / Int'l Joint Research
• [Presentation] What happens for electrons and heat in amphiphilic assemblies - examination with time-resolved spectroscopies (2024)
  • Author(s): Koichi Iwata
  • Organizer: The 17th DAE-BRNS Trombay Symposium on Radiation and Photochemistry
  • Int'l Joint Research / Invited
• [Presentation] Properties of amphiphilic assemblies examined with fast time-resolved spectroscopy - micelles and lipid bilayer membranes (2024)
  • Author(s): Koichi Iwata
  • Organizer: One-day seminar organized under IJAA (North chapter) and DST-JSPS bilateral exchange program
  • Int'l Joint Research / Invited
• [Presentation] Properties of amphiphilic assemblies examined with fast time-resolved spectroscopy - micelles and lipid bilayer membranes (2024)
  • Author(s): Koichi Iwata
  • Organizer: Seminar, Prof. Umapathy’s group, Department of Physical and Inorganic Chemistry, Indian Institute of Science (IISc)
  • Int'l Joint Research / Invited
• [Presentation] What we learn with new time-resolved Raman spectrometers (2023)
  • Author(s): Koichi Iwata
  • Organizer: 12th International Conference on Advanced Vibrational Spectroscopy
  • Int'l Joint Research / Invited
• [Presentation] Basic Events Associated with Chemical Reactions Studied with Time-Resolved Spectroscopy (2023)
  • Author(s): Koichi Iwata
  • Organizer: NYCU-Gakushuin 6th Student Symposium
  • Int'l Joint Research / Invited
• [Presentation] Vibrational Energy Transfer between Photoexcited α-Terthiophene and Metal Nanoparticles Probed with Picosecond Time-resolved Raman Spectroscopy (2023)
  • Author(s): Tsukasa Tokita, Koichi Iwata
  • Organizer: Time Resolved Vibrational Spectroscopy 2023
  • Int'l Joint Research
• [Presentation] Electrons Released from Photoexcited Organic Molecules in Solution Recorded with Femtosecond Time-resolved Near-infrared Spectroscopy (2022)
  • Author(s): Koichi Iwata
  • Organizer: The 8th Quantum Science (QS) symposium, ICCMSE 2022-Computational Chemistry and Computational Physics
  • Int'l Joint Research / Invited
• [Presentation] Initial Step of Photoinduced Fast Bimolecular Reaction between Terthiophene and Carbon Tetrachloride Examined with Time-Resolved Spectroscopy (2021)
  • Author(s): Yuki Otomo, Tsukasa Tokita, Koichi Iwata
  • Organizer: 11th Asian Photochemistry Conference (APC2021)
  • Int'l Joint Research / Invited
• [Presentation] Simultaneous relaxation of carotenoids in electronic and vibrational states. Time-resolved near-infrared absorption and non-linear Raman study (2021)
  • Author(s): Koichi Iwata, Tomohisa Takaya, Masato Anan, Yohei Kamiya
  • Organizer: The International Chemical Congress of Pacific Basin Societies (Pacifichem 2021)
  • Int'l Joint Research / Invited
• [Presentation] Thermal dissipation process of photoexcited molecule with metal nanoparticles evaluated by picosecond time-resolved Raman spectroscopy (2021)
  • Author(s): Tsukasa Tokita, Koichi Iwata
  • Organizer: The International Chemical Congress of Pacific Basin Societies (Pacifichem 2021)
  • Int'l Joint Research
• [Presentation] Thermal diffusivity of ternary lipid bilayers observed with picosecond time-resolved Raman spectroscopy (2021)
  • Author(s): Chiaki Hiraoka, Tsukasa Tokita, Akira Takakado, Koichi Iwata
  • Organizer: The International Chemical Congress of Pacific Basin Societies (Pacifichem 2021)
  • Int'l Joint Research
• [Presentation] Two-photon ionization mechanism of biphenyl in polar solvents observed with femtosecond time-resolved near-IR absorption spectroscopy (2021)
  • Author(s): Mizuho Kajita, Koichi Iwata
  • Organizer: The International Chemical Congress of Pacific Basin Societies (Pacifichem 2021)
  • Int'l Joint Research
• [Presentation] ターチオフェンと四塩化炭素の光誘起高速二分子反応における反応初期状態検出の試み (2021)
  • Author(s): 大友 由樹，時田 司，岩田 耕一
  • Organizer: 第15回分子科学討論会
• [Presentation] ピコ秒時間分解ラマン分光法で観測した 金属ナノ粒子近傍のS1 α-ターチオフェンの高速振動エネルギー移動 (2021)
  • Author(s): 時田 司，岩田 耕一
  • Organizer: 第15回分子科学討論会
• [Presentation] ピコ秒時間分解分光法による赤血球および大腸菌の生体膜物性測定の試み (2021)
  • Author(s): 平岡 千明，時田 司，高門 輝，岩田 耕一
  • Organizer: 第15回分子科学討論会
• [Presentation] 梶田 瑞穂，髙屋 智久，岩田 耕一 (2021)
  • Author(s): 時間分解近赤外分光法で観測した溶液中での芳香族化合物の光イオン化による電子放出
  • Organizer: 第15回分子科学討論会
• [Presentation] 金属ナノ粒子近傍の S1 ターチオフェンの振動モード選択的な高速熱エネルギー移動過程の観測 (2021)
  • Author(s): 時田 司，岩田 耕一
  • Organizer: 2021年度日本分光学会年次講演会
• [Presentation] ピコ秒時間分解ラマン分光法で観測した Ag ナノ粒子近傍の S1ターチオフェンの急速振動緩和過程 (2020)
  • Author(s): 時田司, 岩田耕一
  • Organizer: 分子科学会オンライン討論会
• [Presentation] ピコ秒時間分解ラマン分光法による金属ナノ粒子存在下における S1 α-ターチオフェンの構造変化と急速振動緩和過程の観測 (2020)
  • Author(s): 時田司, 岩田耕一
  • Organizer: 2020年日本分光学会年次講演会
• [Presentation] ピコ秒時間分解ラマン分光法を用いた三成分系人工脂質二重膜における熱拡散定数の評価 (2020)
  • Author(s): 平岡千明，時田司，高門輝，岩田耕一
  • Organizer: 2020年日本分光学会年次講演会
• [Presentation] Perspective of time-resolved spectroscopy in near-infrared for studying loose electrons-polyene excited sates, solvated electrons and photoinduced charge carriers (2020)
  • Author(s): Koichi Iwata
  • Organizer: The 8th International Conference on Perspectives in Vibrational Spectroscopy
  • Int'l Joint Research / Invited
• [Presentation] 高感度高安定フーリエ変換限界ピコ秒時間分解ラマン分光法の試み (2019)
  • Author(s): 時田司，高屋智久，岩田耕一
  • Organizer: 2019年日本分光学会年次講演会
• [Presentation] Electron Solvation Processes Examined with Femtosecond Time - resolved Near-infrared and Visible Absorption Spectroscopy (2019)
  • Author(s): Koichi Iwata
  • Organizer: 15th International Conference of Computational Methods in Science and Engineering
  • Int'l Joint Research / Invited
• [Presentation] Development of highly stable and Fourier transform limited picosecond time-resolved Raman spectrometer (2019)
  • Author(s): Tsukasa Tokita, Tomohohisa Takaya, Koichi Iwata
  • Organizer: Tenth International Conference on Advanced Vibrational Spectroscopy
  • Int'l Joint Research
• [Presentation] 電子励起状態分子の表面増強ラマン分光法の試み (2019)
  • Author(s): 時田 司，高屋 智久，岩田 耕一
  • Organizer: 第13回分子科学討論会
• [Presentation] Attempt of surface enhanced Raman spectroscopy for electronically excited molecules (2019)
  • Author(s): Tsukasa Tokita, Tomohisa Takaya, Koichi Iwata
  • Organizer: 2019 Gakushuin-NCTU Symposium
  • Int'l Joint Research
• [Presentation] Development of picosecond time-resolved Raman spectrometer with simple optical setup and high stability (2018)
  • Author(s): Tsukasa Tokita, Tomohisa Takaya, Koichi Iwata
  • Organizer: 26th International Conference on Raman Spectroscopy
  • Int'l Joint Research
• [Presentation] Development of stable picosecond time-resolved Raman spectrometer with simple optical setup (2018)
  • Author(s): Tsukasa Tokita, Tomohisa Takaya, Koichi Iwata
  • Organizer: 4th NCTU-Gakushuin Symposium
  • Int'l Joint Research
• [Presentation] 高安定ピコ秒時間分解ラマン分光計の製作と 過渡分子種の高感度検出の試み (2018)
  • Author(s): 時田 司，高屋 智久，岩田 耕一
  • Organizer: 第12回分子科学討論会
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