Development of Frequency Swept EPR under the Low Magnetic Field

利用电子顺磁共振（EPR）和振动（拉曼）光谱两种技术进行了合作研究，得到了以下结果。对于EPR，我们与四个实验室合作，柏林自由大学的Moebius教授，意大利帕多瓦大学的Corvaja教授，耶路撒冷希伯来大学的Levanon教授和德国弗赖堡大学的Kothe教授，我们在那里做了实验和讨论。为了拉曼，乌诺博士参观了钱皮恩教授的实验室。并进行了两周的实验。在金属（Zn和Mg）卟啉-氮氧自由基体系中，我们首次用EPR技术观察到了激发态的二重态和四重态，并用高频（95 GHz）EPR很好地分离了它们.本文首次在溶液中用金属卟啉和酞菁化合物观察到了三重激发态的EPR信号。通过光谱模拟，对Jahn-Teller分裂态和分子运动进行了平均分析，表明该方法对溶液中激发三重态性质的分析非常有用.二维（2D）脉冲EPR技术的发展，以确定自旋多重态的激发和应用于研究系统的双自由基连接富勒烯。在激发态下，首次观察到了激发态五重态，并对其进行了明确的归属和电子结构分析.对氧化的细胞色素P450进行了共振拉曼研究，并成功地在活性中心归属了一个结构标记带。Fe-O-O弯曲模式的观察揭示了酶的结构特异性。

Collaborative studies were made by use of two techniques, electron paramagnetic resonance(EPR) and vibrational (Raman) spectroscopy, giving the following results.For EPR, we collaborated with four laboratories, Prof.Moebius's at Free University of Berlin, Prof.Corvaja's at Padova University in Italy, Prof.Levanon's at Hebrew University of Jerusalem, and Prof.Kothe's at Freiburg University in Germany, where we made the experiments and discussion. For Raman, Dr.Unno visited Prof.Champion's lab. at Northeastern University of Boston and ran experiments for two weeks.1. In a system of metallo(Zn and Mg) porphyrin-nitroxide radical, we observed excited doublet and quartet states for the first time by EPR techniques, which are separated nicely by means of high frequency (95 GHz) EPR.2. EPR signals of the excited triplet states were observed for the first time in solution using metallo-porphyrins and -phthalocyanines up to +90℃. From the spectral simulation, averaging over the Jahn-Teller split states and molecular motions were analyzed , which indicates that this method is very useful for analyses of excited triplet properties in solution.3. Two dimensional (2D) pulsed EPR techniques were developed to determine spin multiplicity of the excited multiplet states and applied to studies in systems of bisradical linked fullerene. On excitation the excited quintet states were observed and definitely assigned for the first time and the electronic structures were analyzed.4. The resonance Raman investigation was made for oxygenated cytochrome P450 and a structural marker band was successfully assigned at the active site. The observation of the Fe-O-O bending mode reveals structural specificity of the enzyme.