Trap Mediated Energy Transport via Vibronic Resonance

Abstract

Controlling energy transfer through vibronic resonance is an interesting possibility. Exact treatment of non-adiabatic vibronic coupling is necessary to fully capture its role in driving energy transfer. However, exact treatment of vibrations in extended systems is expensive, sometimes requiring oversimplifying approximations to reduce vibrational dimensionality, and do not provide physical insights into which specific vibrational motions promote energy transport. Here we derive effective normal modes for excitonically coupled aggregates which reduce the overall high-dimensional vibronic Hamiltonian into independent one-dimensional Hamiltonians. Applying this approach on a trimer toy model, we demonstrate trap-mediated energy transport between electronically uncoupled sites. Bringing uncoupled sites into vibronic resonance converts the `trap' into a `conduit' for population transfer, while simultaneously minimizing trapped excitations. Visualizing energy transfer along the aggregate normal modes provides non-intuitive insights into which specific vibrational motions allow for trap-mediated energy transport by promoting vibronic mixing.