Development of Frequency Swept EPR under the Low Magnetic Field

本研究的目的是为了有效地观察溶液中激发三重态和激发多重态的信号而研制EPR装置。研究结果如下：1.溶液中激发态多重态的磁场扫描EPR观测（1）首次在溶液中观测到卟啉、酞菁和亚酞菁的激发三重态和激发四重态的BPR信号。(2)利用这些信号对自旋弛豫、电子转移和能量转移的自旋和反应动力学进行了独特的分析.扫频式EPR装置的研制（1）在各种谐振器中选择并制作了环隙谐振器（LGR）作为扫频谐振器。(2)在L波段（0.8- 1.5GHz），用EPR方法观察了溶液中卟啉和酞菁的激发态三重态。(3)该装置的性能如下：时间分辨率; 80 ns，微波功率; 100 mW（使用放大器时为1 W），Q值; 300，谐振腔尺寸，r = 3 mm，灵敏度; 3 × 10 ~（-4）<12>自旋/G。零磁场和低磁场的稳定化通过制作相对于正常方向的反向磁场的电源，实现了0-50 mT的磁场稳定化。如上所述，成功实现了主要的三点。但在零磁场下，我们未能观察到溶液中的三重态信号，因此还需在微波放大能力、激光发生器灵敏度等方面进一步改进。

The purpose of the study is developnient of the EPR apparatus in order to observe the signals effectively for excited triplets and excited multiplets in solution. The results are summarized as follows.1. Observation of excited multiplets in solution by means of magnetic field-swept EPR(1) BPR signals of excited triplets and an excited quartet of porphyrins, phthalocyanine, and subphthalocyanine were observed for the first time in solution.(2) Spin and reaction dynamics of spin relaxations, electron transfer, and energy transfer were analysed uniquely by using these signals.2. Development of a frequency-swept EPR apparatus(1) The loop-gap-resonator(LGR) was selected and made among various resonators as a frequency-swept resonator.(2) L-band (0.8-l.5 GHz) EPR was constructed for an observation of excited triplets of porphyrin and phthalocyanine in solution.(3) The performance of the apparatus is the following : time resolution ; 80 ns, power of microwave ; 100 mW (1W in use of the amplifier), Q value ; 300, resonator size, r = 3 mm. and sensitivity ; 3 x 10^<12> spins/G.3. Stabilization of the zero and low magnetic fieldsBy making a power supply for the reverse magnetic field with respect to the regular direction, the magnetic field of 0-50 mT was stabilized.As described above, the major three points were successfully realized. But we failed to observe triplet signals in solution under the zero magnetic field and have to improve further the machine on ability of microwave amplifier, sensitivity of LGR, and so on.