| Project/Area Number |
12640507
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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 | RIKEN (The Institute of Physical and Chemical Reseach) |
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Principal Investigator |
WAKASA Masanobu RIKEN, Molecular Photochemistry Lab., Senior Research Scientist, 分子光化学研究室, 先任研究員 (40202410)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2000: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Magnetic Field Effect / Photochemical Reaction / Homogeneous Solution / picosecond laser flash photolysis / Δg mechanism / thiyl radical / Benzophenone / spindynamics / ピコ秒ダイナミクス / 均一系溶媒中 / 硫黄ラジカルの反応 / ラジカル対 / スピン変換過程 |
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| Research Abstract |
We have developed a picosecond laser flash photolysis apparatus with a convenient picosecond pulse laser as an excitation light source and a streak camera to measure transient absorptions. The hydrogen abstraction reaction of triplet 4-methoxy-benzophenone with thiophenol at 265 K was reinvestigated with this apparatus under magnetic fields of 0-1.7 T. The magnetic field effects (MFEs) on this reaction were successfully observed with - 1OO ps time-resolution. The decay rate constant of the generated radical pair was found to increase from 3.42 x 1 09 s^<-1> to 4.15 x 10^9 s^<-1> with increasing magnetic field from 0 T to 1.7 T. The observed magnetic field effects can be explained by the Ag mechanism. Using the simple kinetics model with the Ag mechanism, we tentatively obtained the rate constants of the escape process from the pair (k_<esc>) and the T-S spin conversion process (k_<T-S>) at 0 T and 1.7 T to be 1.97 x 109 s^<-1>, 1.45 x 10^9 s^<-1>, and 2.12 x 10^9 s^<-1>, respectively. From these results, this apparatus is found to be simple and useful for studying MFES on the picosecond spin dynamics.
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