文章基本信息

标题：Magnetic characterization of the primary state of bacterial photosynthesis
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作者：J. R. Norris ; M. K. Bowman ; D. E. Budil 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：18
页码：5532-5536
DOI：10.1073/pnas.79.18.5532
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The results of reaction yield-detected magnetic resonance (RYDMR) experiments carried out on modified bacterial photosynthetic reaction centers (RCs) are interpreted in terms of a model that assigns the initial charge-separated radical ion-pair state, PF, as the carrier of the spectrum. The radical pair theory, which has been invoked to explain magnetic field effects in RCs, was significantly expanded to take into consideration the electron dipole-dipole interaction. It is shown that this is the largest interaction between the components of the radical ion pair. Quantum statistical calculations are described simulating the RYDMR spectra and low-field effects in quinone-depleted RCs. The experimental data on which the simulations are based are (i) the magnitude of the field effect at 3,000 G, (ii) the field at which 0.5 of the maximal field effect is observed, (iii) the PF population as a function of time at zero magnetic field, (iv) the RYDMR linewidth for low microwave field strength, (v) the RYDMR intensity and width as a function of microwave field, and (vi) the maximum RYDMR intensity at HI [~=] 2|J|. With this information it was found possible to characterize PF in terms of four parameters, two containing structural information and two with kinetic implications. These are the dipole-dipole interaction, D = -47 {+/-} 10 x 10-4 cm-1; the exchange interaction, J = -7.5 {+/-} 1.9 x 10-4 cm-1; and the inverse rate constants of the decay of the radical pair states with singlet and triplet spin functions, respectively, kS-1 = 15 {+/-} 4 nsec and kT-1 = 1.8 {+/-} 0.2 nsec. The structural and dynamic implications of these parameters are discussed.
关键词：primary radical pair ; reaction yield-detected magnetic resonance ; optically detected magnetic resonance ; electron-electron dipolar interaction