Path-integral Monte-Carlo simulations for electronic dynamics on molecular chains: II. Transport across impurities

TL;DR

This paper uses advanced path integral Monte Carlo simulations to analyze electron transfer across molecular chains with impurities, revealing how defect energies influence transfer rates and the approach to steady state.

Contribution

It introduces an improved real-time PIMC method to study electron dynamics on molecular chains with impurities, providing new insights into transfer rates and steady state behavior.

Findings

Transfer rates are enhanced at specific defect site energies.

Steady state is reached faster than total transfer time.

Long-time behavior can be modeled with a sequential transfer approach.

Abstract

Electron transfer (ET) across molecular chains including an impurity is studied based on a recently improved real-time path integral Monte Carlo (PIMC) approach [J. Chem. Phys. {\bf 121}, 12696 (2004)]. The reduced electronic dynamics is studied for various bridge lengths and defect site energies. By determining intersite hopping rates from PIMC simulations up to moderate times, the relaxation process in the extreme long time limit is captured within a sequential transfer model. The total transfer rate is extracted and shown to be enhanced for certain defect site energies. Further, it is revealed that the entire bridge compound approaches a steady state on a much shorter time scale than that related to the total transfer which allows for a simplified description of ET along donor-bridge-acceptor systems in the long time range.