title: Identifying electron transfer coordinates in donor-bridge-acceptor systems using mode projection analysis.
abstract: We report upon an analysis of the vibrational modes that couple and drive the state-to-state electronic transfer branching ratios in a model donor-bridge-acceptor system consisting of a phenothiazine-based donor linked to a naphthalene-monoimide acceptor via a platinum-acetylide bridging unit. Our analysis is based upon an iterative Lanczos search algorithm that finds superpositions of vibronic modes that optimize the electron/nuclear coupling using input from excited-state quantum chemical methods. Our results indicate that the electron transfer reaction coordinates between a triplet charge-transfer state and lower lying charge-separated and localized excitonic states are dominated by asymmetric and symmetric modes of the acetylene groups on either side of the central atom in this system. In particular, we find that while a nearly symmetric mode couples both the charge-separation and charge-recombination transitions more or less equally, the coupling along an asymmetric mode is far greater suggesting that IR excitation of the acetylene modes preferentially enhances charge-recombination transition relative to charge-separation.
authors.affiliation: Department of Chemistry, University of Houston, Houston, Texas 77204, USA.
authors.forename: Xunmo
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
authors.forename: Theo
authors.identifier: 0000-0003-4975-0868
authors.initials: T
authors.lastname: Keane
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
authors.forename: Milan
authors.initials: M
authors.lastname: Delor
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
authors.forename: Anthony J H M
authors.initials: AJ
authors.lastname: Meijer
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
authors.forename: Julia
authors.initials: J
authors.lastname: Weinstein
authors.affiliation: Department of Chemistry, University of Houston, Houston, Texas 77204, USA.|Department of Physics, University of Houston, Houston, Texas 77204, USA.
authors.forename: Eric R
authors.identifier: 0000-0002-0775-9664
authors.initials: ER
authors.lastname: Bittner