Electron transfer rates for asymmetric reactions

TL;DR

This paper employs a numerically exact Monte Carlo scheme to study electron transfer rates in asymmetric reactions, revealing detailed dynamics and confirming Marcus theory at high temperatures while uncovering unique low-temperature behaviors.

Contribution

It introduces a precise computational approach for asymmetric electron transfer and explores the crossover between nonadiabatic and adiabatic regimes, including low-temperature peculiarities.

Findings

Good agreement with Marcus theory at high temperatures when dynamical effects are included.

Discovery of rapid transient dynamics and backflow in strongly asymmetric systems at low temperatures.

Temperature renormalization improves the match between theory and simulation.

Abstract

We use a numerically exact real-time path integral Monte Carlo scheme to compute electron transfer dynamics between two redox sites within a spin-boson approach. The case of asymmetric reactions is studied in detail in the least understood crossover region between nonadiabatic and adiabatic electron transfer. At intermediate-to-high temperature, we find good agreement with standard Marcus theory, provided dynamical recrossing effects are captured. The agreement with our data is practically perfect when temperature renormalization is allowed. At low temperature we find peculiar electron transfer kinetics in strongly asymmetric systems, characterized by rapid transient dynamics and backflow to the donor.