1989 Fiscal Year Final Research Report Summary
Construction of Simultaneous Observation System of Time-Resolved ESR and Nanosecond Transient Absorption Spectra
| Project/Area Number |
63840012
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 |
TERO Shozo Tohoku University, Chemical Research Institute of Non-Aqueous Solutions, Associate Professor, 非水溶液化学研究所, 助教授 (80111318)
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| Co-Investigator(Kenkyū-buntansha) |
ONODERA Shinji Tohoku University, Chemical Research Institute of Non-Aqueous Solutions, Associa, 非水溶液化学研究所, 助教授 (30006316)
IKEGAMI Yusaku Tohoku University, Chemical Research Institute of Non-Aqueous Solutions, Profess, 非水溶液化学研究所, 教授 (60006294)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Time-resolved ESR / Nanosecond spectroscopy / Transient absorption / Laser photolysis / Photochemistry |
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| Research Abstract |
A nanosecond laser photolysis system and an optical transmission cavity for time-resolved ESR spectroscopy were constructed. We applied the system for several photochemical reactions to measure transient absorption and time-resolved ESR spectra of the short-lived intermediates. The present study clearly shows that this system plays an important role in photochemistry, since the informations obtained from these spectra are complements each of the other.
1. Nanosecond laser photolysis system. For measurements of transient absorption spectra of the short-lived excited triplet states and radical intermediates generated from laser excitation, a nanosecond laser photolysis system was constructed. We obtained desired capability for our purpose.
2. Transmission microwave cavity. We prepared a transmission cavity equipping with a window (5 phi) for laser photolysis. Unloaded Q value is large than 3000. The cavity is able to connect to the transition absorption spectroscopy by optical fibers.
3. Ph
… More
otochemical studies on the reaction mechanism and dynamics. Photochemistry of epoxyketbne derivatives was studied in the presence of electron or hydrogen donating reagents. In the presence of amines, the anion radical of epoxyketone was observed by transient absorption method. The life-time of the radical was determined to be less than 1mus. Although the carbon centered radical generated from the ring opening was not detected by the transient absorption method, it was clearly measured by time-resolved ESR spectroscopy. Therefore, we can determine the photochemical chain reaction mechanism by using the present system.
When free radical shows second order decay, it is usually difficult to determine the molar extinction coefficient. The present system is very useful for the purpose. We can determine the extinction coefficients of shortlived pyridinyl radicals generated from the laser photolysis of the photosensitive dimers. The time-resolved triplet-triplet absorption spectrum of o-nitrobiphenyl was also observed. Less
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