title: Decoherence and quantum interference in a four-site model system: mechanisms and turnovers.
abstract: We study quantum interference effects in a four-level system which can be used as a minimal model to understand such behavior in systems from synthetic molecular structures to the photosystem-1 reaction center. The effects of environmental decoherence and relaxation on the electron transfer rate are investigated for several types of decoherence processes. The rate as a function of decoherence amplitude shows Kramers turnover, as expected. However, various decoherence processes affect the quantum interference differently. It is shown that when the bridge sites are not dephased the superexchange transfer is enhanced by constructive quantum interference. Dephasing on bridge sites opens a (classical) diffusive channel for fast electron transfer, which can dominate the superexchange current and reduce the constructive quantum interference.
authors.affiliation: Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois, USA. m-zarea@northwestern.edu
authors.forename: Mahdi
authors.initials: M
authors.lastname: Zarea
authors.forename: Daniel
authors.initials: D
authors.lastname: Powell
authors.forename: Nicolas
authors.initials: N
authors.lastname: Renaud
authors.forename: Michael R
authors.initials: MR
authors.lastname: Wasielewski
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ratner
mesh_terms: D008958:Models, Molecular; D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000378:metabolism; D011789:Quantum Theory
chemical_list: D045331:Photosystem I Protein Complex