1999 Fiscal Year Final Research Report Summary
Sequential photochemical processes in biological and artificial molecular systems
| Project/Area Number |
09304056
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | HOKKAIDO UNIVERSITY |
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Principal Investigator |
YAMAZAKI Iwao Grad. School of Eng., Hokkaido Univ., Pro., 大学院・工学研究科, 教授 (80002111)
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| Co-Investigator(Kenkyū-buntansha) |
AKIMOTO Seiji Grad. School of Eng., Hokkaido Univ., Asso. Pro., 大学院・工学研究科, 助手 (40250477)
NISHIMURA Yoshinobu Grad. School of Eng., Hokkaido Univ., Asso. Pro., 大学院・工学研究科, 助手 (60218211)
OHTA Nobuhiro Research Institute for Electronic Science, Hokkaido Univ., Pro., 電子科学研究所, 教授 (70113529)
MIMURO Mamoru Faculty of Sci., Yamaguchi Univ., Pro., 理学部, 教授 (40142004)
OSUKA Atsuhiro Grad. School of Sci., Kyoto Univ., Pro., 理学研究科, 教授 (80127886)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Organized molecular systems / Electron transfer / Excitation transfer / Femtosecond laser / Photosynthesis / Porphyrins |
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| Research Abstract |
This research project aims at presenting a new aspect of photochemical processes in highly organized molecular systems in which reacting molecules are located with close proximity and optimal orientation. The reaction dynamics of ultrafast and non-equilibrium processes in electron transfer and excitation transfer were monitored with femtosecond time-resolved fluorescence spectroscopy. The result of this study is summarized in the following. (1) In Langmuir-Blodgett multilayers, it was found that the inter- and intra-layer excitation transfer took place much faster at room temperature (ca. 10 ps) than in 10K (ca. 50 ps). The theoretical analyses suggest that the spatical fluctuation of molecules may play an important role in excitation transfer. (2) In artificial porphyrin arrays and photosynthetic carotenoid-chlorophyll systems, the excitation energy transfer occurs directrly from the donor S2 state during 80-140 fs before thermal equilibration. This finding violates the well-known Kasha's rule that the photochemical reaction proceeds from the thermally equilibrated lowest excited state. (3) External electric field effect It was found that the electron transfer in LB films undergoes the external electrid field and its reaction rate depend stronly on the initially excited state. The results of the project are now directed toward development of quantum computing elecments and photo-switching molecular devices.
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