1988 Fiscal Year Final Research Report Summary
Enhancement of Time-resolution of Laser Photolysis ESR Spectrometer and the application for Electron Spin Relaxation Mechanism
| Project/Area Number |
62470001
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理化学一般
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SHOZO Tero Chemical Research Institute of Non-Aqueous Solutions, Tohoku University, 非水溶液化学研究所, 助教授 (80111318)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Laser Photolysis / Time-Resolved ESR / Photochemistry / 励起三重項状態 |
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| Research Abstract |
1. Enhancement of time-resolution of laser photolysis ESR spectrometer. Responce time of our time-resolved ESR spectrometer was improved by equipping with a digitizer(Sony Tektronix RTD-710), which has high speed sampling rate(5 ns) and high resolution for the signal intensity(10 bit). We were able to obtain better signal-to-noize ratio by using a wide-band preamplifier(Stanford SR-440).
2. Photochemical reaction mechanism and the excited triplet states o-quinones. The excited triplet states of non-phosphorescent 1,2-naphthoquinone and phosphorescent 9,10-phenanthrenequinone were observed in several glassy matrices at low temperatures by time-resolved ESR method. Notable solvent effects on the zero-field splitting constants were observed indicating the small energy separation between n【product】<@D1*@>D1 and 【product】【product】<@D1*@>D1 states in these o-quinones. CIDER spectra of the semiquinone radical produced by photoinduced hydrogen abstraction from solvent reflect the electronic character of the excited triplet states. Photochemistry of several o-quinones in the presence of amines were also studied.
3. Time-resolved ESR study of triplet ketoamines generated by intramolecular proton transfer in free Schiff bases. Non-phosphorescent triplet states of the ketoamine forms of several free Schiff bases generated by intramolecular proton transfer have been observed by using time-resolved ESR technique.
4. Time-resolved ESR studies on the excited triplet states and photoenolization of 2-methylacetophenone and related molecules. Non-phosphorescent excited triplet states of photoenols generated from the intra-molecular hydrogen abstraction of o-methylacetophenone and related compounds were measured, together with their phosphorescent excited triplet states by time- resolved ESR method at low temperatures. The obtained small D value (0.060 cm^<-1>) suggests the biradical character of the triplet enol.
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