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Construction and Application of a Multi-Function Laser Photolysis ESR

多功能激光光解ESR的构建及应用

基本信息

批准号：
06554032
负责人：
HIROTA Noboru
金额：
$ 7.17万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06554032/
关键词：
ESR laser photolysis CIDEP transient absorption time-resolved ESR 光検出ESR

项目摘要

In order to make a multi functional laser photolysis ESR spectrometer by combining an ESR spectrometer with various equipments for spectroscopic measurements the followings were made.(1) A variable wavelength pulsed-TAG laser system was introduced to perform laser photolysis at various wavelengths in the visible to UV region. (2) An ESR cavity was modified to do simultaneous measurements of CIDEP and laser photlysis. (3) Simultaneous measurements of ESR,reansient absorption and fluorescence were tried using an ESR cavity. (4) The ESR spectrometer was modified to do optical detection of ESR by inducing microwave transitions among spin-sublevels. After checking the performance of the spectrometer system, the follwoing studies were made.1) Studies of the initial processes of photochemical reactions by ESR and transient absorption : We have made a detailed investigation on the CIDEP of redicals produced by hyrogen abstraction reactions of azaaromatic molecules by 2-propanol. The observed CIDEP signals are strongly dependent on the concentration, the excitation light intensity and the delay time, showing that several different CIDEP mechanisms are involved. It was concluded that the net emissive polarization observed at relatively high concentrations are likely due to the radical-triplet pair mechanism (RTPM). The time profiles of the observed signals were comparaed with the theoretical predictions made on the basis of possible reaction and relaxation schemes. The effect of the T-T annihilation on the CIDEP signal rise was also clarified.2) CW and FT time-resoved ESR studies of photochemical reactions and CIDEP : Detailed investigations on the quenching rates of various molecules by 2-propanolyl radical and the magnetic field dependence of the triplet mechanisms of CIDEP were made and much new information was obtained.

为了制作多功能激光光解ESR光谱仪，将ESR光谱仪与各种光谱测量设备相结合，主要做了以下工作：(1)介绍了一种可变波长脉冲标签激光系统，用于在可见光到紫外区进行不同波长的激光光解。(2)对ESR腔进行了改进，实现了CIDEP和激光光解的同时测量。(3)利用ESR腔体同时测量ESR、剩余吸收和荧光。(4)对ESR光谱仪进行了改进，通过在自旋-子能级之间诱导微波跃迁来实现对ESR的光学检测。在考察了光谱仪系统的性能后，进行了以下研究：1)用ESR和瞬时吸收研究了光化学反应的初始过程：我们对异丙醇抽提氮杂芳烃分子产生的自由基的CIDEP进行了详细的研究。观察到的CIDEP信号强烈依赖于浓度、激发光强度和延迟时间，这表明CIDEP涉及几种不同的机制。结果表明，在较高浓度下观察到的净发射偏振可能是由于自由基-三重态对机制(RTPM)。将观测信号的时间分布与根据可能的反应和松弛方案所作的理论预测进行了比较。阐明了T-T湮没对CIDEP信号上升的影响。2)光化学反应和CIDEP的CW和FT时间分辨ESR研究：详细研究了各种分子被2-丙基自由基猝灭的速率和CIDEP三重态机制的磁场依赖性，获得了许多新的信息。