title: Unusual distance dependences of electron transfer rates.
abstract: Usually the rates for electron transfer (kET) decrease with increasing donor-acceptor distance, but Marcus theory predicts a regime in which kET is expected to increase when the transfer distance gets longer. Until recently, experimental evidence for such counter-intuitive behavior had been very limited, and consequently this effect is much less well-known than the Gaussian free energy dependence of electron transfer rates leading to the so-called inverted driving-force effect. This article presents the theoretical concepts that lead to the prediction of electron transfer rate maxima at large donor-acceptor distances, and it discusses conditions that are expected to favor experimental observations of such behavior. It continues with a consideration of specific recent examples in which electron transfer rates were observed to increase with increasing donor-acceptor distance, and it closes with a discussion of the importance of this effect in the context of light-to-chemical energy conversion.
authors.affiliation: Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland. oliver.wenger@unibas.ch.
authors.forename: Martin
authors.initials: M
authors.lastname: Kuss-Petermann
authors.forename: Oliver S
authors.initials: OS
authors.lastname: Wenger