Optimization of energy transport in the Fenna-Matthews-Olson complex via site-varying pigment-protein interactions.

Energy transport in photosynthetic systems can be tremendously efficient. In particular, we study exciton transport in the Fenna-Mathews-Olson (FMO) complex found in green sulphur bacteria. The exciton dynamics and energy transfer efficiency depend on the interaction of excited chromophores with their environment. Based upon realistic, site-dependent models of the system-bath coupling, we present results that suggest that this interaction may be optimized in the case of FMO. Furthermore we verify two transport pathways and note that one is dominated by coherent dynamics and the other by incoherent energy dissipation. In particular, we note a significant correlation between energy transport efficiency and coherence for exciton transfer from bacteriochlorophyll (BChl) 8 to BChl 4.