Impact of Spatial Inhomogeneity on Excitation Energy Transport in the Fenna-Matthews-Olson Complex

TL;DR

This paper investigates how spatial inhomogeneities affect excitation energy transfer in the FMO complex using exact spectral density treatments, revealing transport pathways through coherence analysis.

Contribution

It introduces a rigorous analysis of energy transport pathways in FMO considering accurate spectral densities and coherence-population relations.

Findings

Spatial inhomogeneity impacts energy transfer pathways.

Coherence relates to population derivatives in FMO.

Identified specific pathways of excitation energy transport.

Abstract

The dynamics of the excitation energy transfer (EET) in photosynthetic complexes is an interesting question both from the perspective of fundamental understanding and the research in artificial photosynthesis. Challenges persist in numerically simulating these systems both in parameterizing them and following their dynamics over long periods of time. Over the past decade, very accurate spectral densities have been developed to capture spatial inhomogeneties in the Fenna-Matthews-Olson (FMO) complex. We investigate the dynamics of FMO with an exact treatment of various theoretical spectral densities. Because FMO has Hamiltonian elements that connect most of the bacteriochlorophyll sites together, it becomes difficult to rigorously identify the energy transport pathways in the complex. We use the recently introduced ideas of relating coherence to population derivatives to analyze the transport process and reveal some of the pathways.