| Project/Area Number |
09640602
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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 | Kyoto University |
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Principal Investigator |
HARA Kimihiko Kyoto University, Graduated School of Science, Lecturer, 大学院・理学研究科, 講師 (80025436)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Dynamic solvent effect / Isomerization / Twisted intramolecular charge-transfer / Time-resolved fluorescence / Kramers turnover / Solvation time / Pressure effect / Viscosity effect / 分子内電荷移動 / 動的ストークスシフト / 蛍光スペクトル |
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| Research Abstract |
The purpose of this project is to understand the "dynamic solventeffect" in the isomerizations with large amplitude rotational motion. Following two main subjects are included ; 1) dynamic solvent effect in theisomerization acompanying with intramolecular charge-transfer and 2)dynamic solvent effect in the non-polar isomerization in non-polar solvent. Here, the high pressure technique has been employed as a powerful methodfor chnaging solvent viscosity continuously and widely without modifyingthe solvent potential energy.
1) Dynamic solvent effect of the isomerization with charge-transfer : The rate-constant of "twisted intramolecular charge-transfer (TICT)" stateformation (kTICT) for 4-(N,N dimethylamino)trinitrophosphine (DMATP) hasbeen determined as a function pressure. kTICT has been studied as afunction of solvent shear viscosity. Solvation has been discussed byusing longitudinal relaxation of solvent (tL) as a measure of solvationtime scale. We found that the reaction path is understood as the shiftfrom solvation controlled to intramolecular vibration controlled scheme.
2) Dynamic solvent effect on non-polar isomerization in non-polarsolvent : The reaction system studied is the Si state isomerization of2-vinylanthracene (I) and 2,2 propenylanthracene (II). The rate constantsof both isomerization reactions have been determined in the series ofalkane solvents frome supercritical ethane to compressed liquid phaseoctane. i) In the high viscosity condition at high pressure where thereaction is controlled by spatial diffusion, the shows non-Kramers behavior. ii) In low viscosity at low pressure where the reaction iscontrolled by energy diffusion, it increases with a same activation energyas in the liqui phase condition. iii) "Kramers turnover" has been observed.iv) The turnover plateau for II locates in the lower viscosity region ascompared with I.
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