| Project/Area Number |
11640521
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
TAHARA Tahei Institute for Molecular Science, Okazaki National Research Institutes Associate professor, 分子科学研究所, 助教授 (60217164)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Takeuchi Institute for Molecular Science, Okazaki National Research Institutes Research Associate, 分子科学研究所, 助手 (50280582)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | ultrafast spectroscopy / femtosecond / relaxation / photochemistry / time-resolved spectroscopy / coherence / reaction dynamics / condensed phase / ダイナミクス / 光異性化 / 電子緩和 |
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| Research Abstract |
We studied picosecond and femtosecond dynamics of fundamental molecules in sondensed phase using time-resolved vibrational, electronic spectroscopy both in the time and frequency domain. The major outcome of this research project is summarized as follows.
1. We constructed a non-colinear OPA system that generates sub-10 fs optical pulses. Using the ultrashort optical pulse, we carried out pump-probe experiments for S_1 trans-stilbene, and observed beating signals due to the vibrational coherence (V_<25> mode) in the S_1 state.
2. We investigated the vibronic relaxation process of polyatomic molecules in solution, taking tetrace ne as an example. We succeeded in measuring both S_2 and S_1 time-resolved fluorescence, and clarified the electronic relaxation, IVR, vibrational cooling and rotational diffusion process which successively occur after S_2←S_1 photoexcitation.
3. We studied photoisomerization of azobenzene by picosecond Raman and femtosecond fluorescence spectroscopy. The obtained data directly showed that the S_2 state is almost exclusively relaxed to the 'planar' S_1 state. It means that the 'long-time believed' rotational isomerization pathway in the S_2 state does not exist, and that isomerization after S_2 excitation takes place in S_1 state after electronic relaxation.
4. We investigated ultrafast intramolecular proton transfer of 1,8-dihydroxyanthraquinone, and found that tautomer-type fluorescence appears within 50 fs, which mean that proton translocation takes place within 50 fs in the excited state of this molecule.
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