Development of Frequency Swept EPR under the Low Magnetic Field

低磁场下扫频EPR的研制

• 批准号: 08554025
• 负责人: YAMAUCHI Seigo
• 金额: $ 7.04万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08554025/
• 关键词: L band EPR; zero field EPR; triplet in solution; zero field splitting; excited triplet state; excited multiplet; metalloporphyrin; frequency swept EPR; 溶液中の三十項; 周波数可変ESR; 励起三十項状態

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.

本研究的目的是研制EPR装置，以便有效地观测溶液中激发的三重态和多重态的信号。研究结果总结如下：1.研究成果。用扫描磁场EPR观察溶液中的激发态多重态：(1)首次在溶液中观察到了激发三重态和一激发四重态的卟啉、酞菁和亚酞菁的BPR信号。(2)利用这些信号对自旋驰豫、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EPR装置的研制(1)在各种谐振器中选择环隙谐振器(LGR)作为扫频谐振器。(2)搭建了L波段(0.8-1.5 GHz)EPR，用于观察溶液中的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)，Q值；300，谐振器尺寸，r=3 mm。和敏感度；3 x 10^&lt；12；旋转/G.3。零磁场和低磁场的稳定通过对规则方向的反向磁场供电，稳定了0-50mT的磁场。如上所述，成功地实现了主要三点。但在零磁场下，我们无法观察到溶液中的三重态信号，需要进一步提高仪器的微波放大能力、LGR灵敏度等。

项目成果

J.Fujisawa et al.: "First Observation of the Excited Doublet State of a Radical-Triplet Pair in Solution : W-band Time-Resolved Electron Paramagnetic Resonance Spectroscopy" J.Phys.Chem.A.103. 213-216 (1999)

J.Fujisawa 等人：“溶液中自由基-三重态对的激发双重态的首次观察：W 波段时间分辨电子顺磁共振波谱”J.Phys.Chem.A.103。

J.Fujisawa, K.Ishii, Y.Ohba, S.Yamauchi, M.Fuhs, and K.Mobius: "First Observation of the Excited Doublet State of a Radical-Triplet Pair in Solution : W-band Time-Resolved Electron Paramagnetic Resonance Spectroscopy" J.Phys.Chem.A. 103. 213-216 (1999)

J.Fujisawa、K.Ishii、Y.Ohba、S.Yamauchi、M.Fuhs 和 K.Mobius：“首次观察溶液中自由基-三重态对的激发二重态：W 波段时间分辨电子顺磁

J.Fujisawa et al.: "Direct Observation of Electron Spin Polarization Transfer in Triplet-Triplet Energy Transfer between Porphyrins and Fullerene in Fluid Solution" Chem.Phys.Lett.282. 181-186 (1998)

J.Fujisawa 等人：“流体溶液中卟啉和富勒烯之间三重态-三重态能量转移中电子自旋极化转移的直接观察”Chem.Phys.Lett.282。

J.Fujisawa, Y.Ohba, and S.Yamauchi: "Electron Spin Polarization Generated from Interactions between Excited Triplet Porphyrin and Stable Radicals Studied by Time Resolved Electron Paramagnetic Resonance" J.Phys.Chem.101. 434-439 (1997)

J.Fujisawa、Y.Ohba 和 S.Yamauchi：“通过时间分辨电子顺磁共振研究激发三重态卟啉和稳定自由基之间相互作用产生的电子自旋极化”J.Phys.Chem.101。

J.Fujisawa, Y.Ohba, and S.Yamauchi: "A Time-Resoleved Electron Paramagnetic Resonance Study of Excited Triplet Porphyrins in Fluid Solution" J.Am.Chem.Soc.119. 8736-8737 (1997)

J.Fujisawa、Y.Ohba 和 S.Yamauchi：“流体溶液中激发三重态卟啉的时间分辨电子顺磁共振研究”J.Am.Chem.Soc.119。