Construction and Application of a Multi-Function Laser Photolysis ESR

为了将ESR光谱仪与各种光谱测量设备相结合，制成多功能激光光解ESR光谱仪。(1)介绍了一种可变波长脉冲tag激光系统，可在可见光至紫外区进行不同波长的激光光解。(2)改进ESR腔体，同时测量CIDEP和激光光解。(3)在ESR腔中尝试同时测量ESR、瞬时吸收和荧光。(4)改进ESR谱仪，通过诱导自旋亚能级间的微波跃迁进行ESR的光学检测。在检查了光谱仪系统的性能后，进行了以下研究。1) ESR和瞬态吸收光化学反应初始过程的研究：我们对氮杂环分子与2-丙醇的抽氢反应产生的残留物的CIDEP进行了详细的研究。观测到的CIDEP信号强烈依赖于浓度、激发光强度和延迟时间，表明涉及多种不同的CIDEP机制。在相对高浓度下观测到的净发射极化可能是由自由基-三重态对机制（RTPM）引起的。观测到的信号的时间分布与根据可能的反应和弛豫方案所作的理论预测进行了比较。澄清了T-T湮灭对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2-丙醇自由基对不同分子的猝灭速率和CIDEP三重态机制的磁场依赖性，获得了许多新信息。

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.