Electron transfer mechanism and the locality of the system-bath interaction: A comparison of local, semilocal, and pure dephasing models

  • Posted on: 10 July 2014
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TitleElectron transfer mechanism and the locality of the system-bath interaction: A comparison of local, semilocal, and pure dephasing models
Publication TypeJournal Article
Year of Publication2006
AuthorsWeiss E.A, Katz G., Goldsmith R.H, Wasielewski M.R, Ratner M.A, Kosloff R., Nitzan A.
JournalJournal of Chemical Physics
Volume124
Date PublishedFeb 21
ISBN Number0021-9606
Accession NumberISI:000235473500030
Keywordsbridged molecular-systems, brownian-motion, condensed-phase, dissipative quantum dynamics, distance dependence, master equation, redfield equation, relaxation, state, transfer rates
Abstract

We simulate the effects of two types of dephasing processes, a nonlocal dephasing of system eigenstates and a dephasing of semilocal eigenstates, on the rate and mechanism of electron transfer (eT) through a series of donor- bridge-acceptor systems, D-B-N-A, where N is the number of identical bridge units. Our analytical and numerical results show that pure dephasing, defined as the perturbation of system eigenstates through the system-bath interaction, does not disrupt coherent eT because it induces no localization; electron transfer may proceed through superexchange in a system undergoing only pure dephasing. A more physically reasonable description may be obtained via a system-bath interaction that reflects the perturbation of more local electronic structure by local nuclear distortions and dipole interactions. The degree of locality of this interaction is guided by the structure of the system Hamiltonian and by the nature of the measurement performed on the system (i.e., the nature of the environment). We compare our result from this "semilocal" model with an even more local phenomenological dephasing model. We calculate electron transfer rate by obtaining nonequilibrium steady- state solutions for the elements of a reduced density matrix; a semigroup formalism is used to write down the dissipative part of the equation of motion. (c) 2006 American Institute of Physics.

Alternate JournalJ Chem Phys