A Study of Structure of Unstable reaction Intermediates by Pulsed Electron-Nuclear Double Resonance

1.脉冲式电子-核双共振装置的研制对自制的脉冲式EPR装置进行了改进，使之能用于流体溶液中光化学反应的ENDOR实验。(1)设计并制作了一个微波谐振腔，可以同时用射频、微波和激光脉冲辐照样品。(2)脉冲序列发生器的改进我设计并建造了一个同步激光器和脉冲EPR装置的系统。激光脉冲和微波脉冲之间的抖动小于3 ns。(3)外磁场的稳定化构造了利用质子NMR信号的FM检测的高斯计。高斯计可以用来稳定电磁铁。2. EPR测量软件的改进计算机系统和数字信号采样器之间的数据传输速度提高了五到十倍。3.数据分析软件我在我们的光谱分析软件上实现了线性预测分析的快速算法。4.光诱导电子转移的瞬时自由基的观察我试图观察ZnTPP阳离子自由基，它是ZnTPP和苯醌之间光诱导电子转移反应的中间体。我尝试了两种方法：（1）直接法（直接测量ENDOR）和（2）去耦法。遗憾的是，我不能通过现有的仪器和方法观察ENDOR（或去耦）效应。为了观察瞬态自由基的END OR，我必须改进以下几点：（1）照射在样品上的RF功率必须更大，（2）为了改善RF与静磁场之间的正交性，RF线圈必须更刚性。

1. Construction of a Pulsed Electron-Nuclear Double Resonance Instrument a home build pulsed EPR instrument was modified for ENDOR experiments on a photo-chemical reaction in fluid solution. (1) Design and Construction of a Resonator for Pulsed-END OR A microwave resonator was designed and constructed by which I could irradiate a sample with RF, microwave and laser pulse simultaneously. (2) Improveing Pulse Sequencer I designed and constructed a system which synchronized a raser and a pulsed EPR apparatus. A jitter between a laser pulse and a microwave pulse was less than 3 ns. (3) Stabilization of an External Magnetic Field A Gaussmeter which utilized FM-detection of a proton NMR signal was constructed. The Gaussmeter can be used to stabilize an electromagnet. 2. Modification of A Software for EPR Measurements A speed of data transfer between a computer system and a digital signal sampler was improved by a factor of five to ten. 3. Data Analysis Software I implemented a fast algorithm of linear prediction analysis on our spectral analysis software. 4. Observation of A Transient Radical of Photo-Induced Electron Transfer I tried to observe a ZnTPP cation radical which was an intermediate of a photo-induced electron transfer reaction between ZnTPP and benzoquinone. I tried two methods : (1) Direct method (direct measurement of ENDOR) and (2) Decoupling method.Unfortunately I could not observe ENDOR (or decoupling) effect by means of present instrumentation and methods. To observe END OR of a transient radical, I must improve following points : (1) RF power which is irradiated on a sample, must be larger, (2) to improve orthogonality between a RF and a static magnetic field, a RF coil must be more rigid.