An efficient method to calculate excitation energy transfer in light harvesting systems. Application to the FMO complex

TL;DR

This paper introduces a fast, efficient method based on a master equation derived from NMQSD to calculate excitation energy transfer in light-harvesting systems, specifically applied to the FMO complex, accounting for vibrational modes.

Contribution

The paper presents a novel, computationally efficient approach to model excitation energy transfer that incorporates vibrational modes, matching the accuracy of the hierarchical equations of motion.

Findings

Method reproduces HEOM results accurately

Vibrational modes significantly influence transfer dynamics

Transfer calculations are completed within about one minute

Abstract

A master equation, derived from the non-Markovian quantum state diffusion (NMQSD), is used to calculate excitation energy transfer in the photosynthetic Fenna-Matthews-Olson (FMO) pigment-protein complex at various temperatures. This approach allows us to treat spectral densities that contain explicitly the coupling to internal vibrational modes of the chromophores. Moreover, the method is very efficient, with the result that the transfer dynamics can be calculated within about one minute on a standard PC, making systematic investigations w.r.t. parameter variations tractable. After demonstrating that our approach is able to reproduce the results of the numerically exact hierarchical equations of motion (HEOM) approach, we show how the inclusion of vibrational modes influences the transfer.