| Project/Area Number |
10440170
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Japan Advanced Institute of Science and Technology |
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Principal Investigator |
YOSHIHARA Keitaro Japan Advanced Institute of Science and Technology, Professor, 材料科学研究科, 教授 (40087507)
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| Co-Investigator(Kenkyū-buntansha) |
RUBTSOV Igor v. Japan Advanced Institute of Science and Technology, Research Associate, 材料科学研究科, 助手 (70293404)
KUMAZAKI Shigeichi Japan Advanced Institute of Science and Technology, Research Associate, 材料科学研究科, 助手 (40293401)
AONO Shigeyuki Japan Advanced Institute of Science and Technology, Associate Professor, 材料科学研究所, 助教授 (60183729)
HATASHI Takashi Kyushu University, Associate Professor, 大学院・工学研究科, 助教授 (20222226)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥10,000,000 (Direct Cost: ¥10,000,000)
Fiscal Year 1999: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1998: ¥5,900,000 (Direct Cost: ¥5,900,000)
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| Keywords | Vibrational Coherence / Femtosecond / Electron Donor-Acceptor Complex / Intermolecular Interaction non-Condon transition / 非コンドン遷移 / 分子振動 / 低振動モード / コヒーレント振動 / フェムト秒分光 / ノンコンドン遷移 / 水素結合 |
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| Research Abstract |
Ultrashort light pulses can coherently excite vibrations with the frequency smaller than the pulse bandwidth. This coherence can be observed by spectroscopic methods in real time as oscillations and specific knowledge can be gained about dynamics of the particular low frequency vibrational mode. Coherent spectroscopy is currently a separate spectroscopic method to study vibrational relaxation, vibrational dephasing and contribution of particular vibrations to chemical reactions, intermolecular vibrations, molecular recognition in biological systems. Electronic states having a charge-transfer character can be found in many natural molecular systems, for example, in iron porphyrin and in photosynthetic reaction center.
The excited-state dynamics of several electron donor-acceptor complexes was studied by a femtosecond fluorescence up-conversion technique. The spontaneous fluorescence of the complexes exhibits an oscillatory feature superimposed with an ultrafast decay component. The oscillation is assigned to the out-of-plane vibration of the acceptors, for complexes with three different acceptors used, tetracyanoethylene, chloranil, and fluoranil. The peak-shift correlation function shows an ultrafast relaxation attributed mainly to the intramolecular vibrational energy redistribution process superimposed with the oscillatory component that demonstrates the modulation of the transition frequency during the vibration. At the same time the modulation of the mean transition moment is observed, which is an indication of the non-Condon transition. Thus, two mechanisms are observed to be responsible for the oscillations : the modulation of the transition frequency and the modulation of the mean transition moment by the vibrational motion.
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