Interference Between Molecular and Photon Field-Mediated Electron Transfer Coupling Pathways in Cavities

Abstract: Cavity polaritonics is capturing the imagination of the chemistry community because of the novel opportunities it creates to direct chemistry. Electron transfer (ET) reactions are among the simplest reactions, and they also underpin bioenergetics. As such, new conceptual strategies to manipulate and direct electron flow at the nanoscale are of wide-ranging interest in biochemistry, energy science, bio-inspired materials science, and chemistry. We show that optical cavities can modulate electron transfer pathway interferences and ET rates in donor-bridge-acceptor (DBA) systems. We derive the rate for DBA electron transfer systems when they are coupled with cavity photon fields (which may be off- or on-resonance with a molecular electronic transition), emphasizing novel cavity-induced pathway interferences with the molecular electronic coupling pathways, as these interferences allow a new kind of ET rate tuning. We also examined the ET kinetics for both low and high cavity frequency regimes as the light-matter coupling strength is varied. The interference between the cavity-induced and intrinsic molecular coupling pathway interference is defined by the cavity properties, including the cavity frequency and the light-matter coupling interaction strength. Thus, manipulating the cavity-induced interferences with the chemical coupling pathways offers new strategies to direct charge flow at the nanoscale.