The effects of bridge motion on electron transfer reactions mediated by tunneling
This chapter provides an in-depth review of recent developments associated with dynamical effects on electron transfer (ET) processes. It discusses the regimens of validity for standard rate formulations and presents in detail the explicit examples of dynamically coupled electron transfer reactions. It also discusses methods for the computation of tunneling matrix elements, bridge mediated electron transfer rates for fluctuating bridges, the influence of tunneling matrix element fluctuations on the ET rate, the qualitative picture of tunneling matrix element fluctuation effects on the ET rate, quantum nuclear motion and inelastic tunneling, tunneling through a bridge with large conformational freedom, and bimolecular ET kinetics: exploring numerous protein-protein conformations and aqueous coupling pathways between proteins. In conclusion, the theoretical framework and specific applications outlined show a richness that emerges as bridge dynamical effects are added explicitly to the considerations of electron transfer kinetics. Quantum interferences can be manipulated by inelastic tunneling effects; reaction mechanisms can be switched, and bridge-mediated tunneling can be dominated by minority population species. © 2006 Elsevier B.V. All rights reserved.
