Development of Accurate Measuring Methods of Spin Susceptibility

电子自旋共振（ESR）方法已被证明是检测和鉴定具有不成对电子的化学物质的最佳方法，但该方法不适用于化学物质的定量分析。为了保持其实用性并发展其定量特征，我们试图通过使用频谱分析仪代替目前使用的相敏检测方法，或使用电磁喇叭和三板谐振器代替谐振腔来开发替代ESR光谱仪。在本研究项目中，我们研究了：1)在微波频谱分析仪上直接观测载波微波的第一个边带（微波频带ESR）来检测ESR信号；2)通过超外差电路对微波频率进行中频下变频的第一个边带信号进行观测（中频边带ESR）； 3)对微波进行空差检测后的调制频率为100khz的信号进行检测（空差边带ESR）。采用高频可编程频谱分析仪。方法1)和2)表明，检测到的ESR信号的线形是吸收型的，而不是导数型的。因此，这些方法很容易用于估计样品的自旋数（自旋磁化率）。特别是后一种方法对信号的检测非常灵敏。另一方面，方法3)表明，线形是导数的，分析仪频谱可以保留用于高阶线形分析。第三种方法已被证明是非常有用的确定g值超精细耦合常数和线宽的ESR信号检测。基于这些检测方法的特点，研究了具有重要生物学意义的金属的电子结构和功能。对配合物及其反应中间体进行了研究。

Electron spin resonamce(ESR) method has been proved to be best techinique for the detection and identification of chemical species having unpaired elctrons, but this method is not proper for the quantitative analysis of the chemical species. In order to maintain its utilities and develop its quantitative features, we have tried to develop altenative ESR spectrometers by using spectrum analyzers insteas of phase sensitive detection method used so far, or by using sell designs such as electromagnetic horns and triplate resonators instead of the resonant cavity. In this research project we have examined 1) directly to detect the ESR signals by observing 1st sideband of the carrier mictowave on microwave spectrum analyzer (microwave sifeband ESR), 2) to obsarve the signals from the 1st sideband of the intermediate frequency down-converted from the mictowave frequency through a superrheterodyne circuit (IF sideband ESR), and 3) to detect the signals on modulation frequency of 100 kHz after homodyne detection of the mictowave (homodyne sideband ESR), by using a HF programmable spectrum analyzer. Methods 1) and 2) have shown that the line-shape of the detected ESR signals is absorptive rather than derivative. Therefore, these methods are easily applicable to estimate the spin numbers of the samples (spin susceptibility). Especially the latter method has been very sensitive for the detection of the signals. On the other hand, Method 3) has shown that the line shape is derivative and analyzer spectrum can be sarved for the higher-order line-shape analysis. The third method has been proved to be very useful to determine g-value hyperfine coupling constants and line-width of the ESR signals detected. Based on such chatacteristics of the detecting methods, the electronic structure and functions of biologically important metal. complexes and their reaction intermediates have been investigated.