Quantum Electron Transport in Degenerate Donor-Acceptor Systems

TL;DR

This paper presents a rigorous quantum mechanical theory for electron transfer in degenerate donor-acceptor systems, highlighting how initial quantum coherence can significantly enhance transfer efficiency.

Contribution

It introduces a new mathematical framework for quantum transfer in degenerate systems and explicitly calculates transfer rates and efficiencies considering initial coherence.

Findings

Quantum coherence enhances transfer efficiency.

Coherent initial states can achieve near 100% efficiency.

Incoherent states significantly reduce transfer efficiency.

Abstract

We develop a mathematically rigorous theory for the quantum transfer processes in degenerate donor-acceptor dimers in contact with a thermal environment. We calculate explicitly the transfer rates and the acceptor population efficiency. The latter depends critically on the initial donor state. We show that quantum coherence in the initial state enhances the transfer process. If the electron is initially shared coherently by the donor levels then the efficiency can reach values close to 100%, while an incoherent initial donor state will significantly suppress the efficiency. The results are useful for a better understanding of the quantum electron transport in many chemical, solid state, and biological systems with complex degenerate and quasi-degenerate energy landscapes.