Exact results for long-range bridge-mediated electron transfer

¹ Department of Applied Physics, Chalmers University of Technology S-412 96 Göteborg, Sweden
² Boreskov Institute of Catalysis, Russian Academy of Sciences Novosibirsk 630090, Russia

Corresponding authors: zhdanov@fy.chalmers.se zhdanov@catalysis.nsk.su

Received: 8 April 2002
Accepted: 11 June 2002

Abstract

The rate constant of long-range electron transfer is proportional to , where is the electronic coupling between the donor and the acceptor. Particles located between the donor and the acceptor may increase the coupling by forming a bridge for electron tunneling. Analysing this effect, we derive an accurate asymptotic expression for in the case when the interaction of an electron with the donor, the acceptor and the bridge is represented as a sum of the Dirac delta-functions. Comparing the exact results with those obtained by using the conventional approach based on combination of atomic orbitals, we show that the latter approach may overestimate by several orders of magnitude.