Bridge-Mediated Excitation Energy Transfer Pathways through Protein Media: a Slater Determinant-Based Electronic Coupling Calculation Combined with Localized Molecular Orbitals

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• 作者：Tsutomu Kawatsu ; Kenji Matsuda ; Jun-ya Hasegawa
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：October 6, 2011
• 年：2011
• 卷：115
• 期：39
• 页码：10814-10822
• 全文大小：1059K
• 年卷期：v.115,no.39(October 6, 2011)
• ISSN：1520-5215

文摘

A computational method for calculating electronic coupling and pathway of electron transfer (ET) has been extended to that for excitation energy transfer (EET). A molecular orbital (MO)-based description has been generalized to one based on Slater determinants. This approach reduces the approximations used for the Green鈥檚 function method from the perturbation of chemical-bond interactions to the perturbation of the configuration interactions. It is, therefore, reasonable to apply this method to EET, which involves the transfer of an electron鈥揾ole pair. To represent EET donor, acceptor, and bridge states, we adopted recently developed localized molecular orbitals (LMOs) for constructing locally excited determinants. The LMO approach provides a chemically meaningful interpretation of how each local excitation on the bridge contributes to the total electronic coupling of the EET. We applied the method to six model peptides and calculated their electronic couplings as well as the direct and through-peptide terms. Although the through-peptide term is usually negligibly small compared with the direct term, it can dominate the EET reaction in appropriate situations. The direct term dominates in long-range interactions because the indirect term decays in shorter distances.