Extended Delocalization Directs Absorption in Purple Bacteria
In photosynthetic purple bacteria, efficient excitation energy transfer from light harvesting (LH) units to the reaction center (RC), where charge separation powers metabolism, benefits from delocalization within single LH units or the RC. We show experimentally and theoretically that extended delocalization over multiple structures is important on the short time scale of absorption, as it generates an appreciable increase in direct absorption at the RC. Interestingly, the requirements for directed absorption are different from those for fast transfer, hence we argue the processes are independent, albeit complementary, facilitators of charge separation.
Host: Luis Orozco