Quantum dynamics of electron transfer in single-molecule systems coupled to polaritons: A macroscopic quantum electrodynamics approach

Controlling electron transfer and related chemical processes through polaritons has emerged as a promising direction in chemical physics. We present a general framework for electron transfer in molecules strongly coupled to polaritons. The theory is formulated within macroscopic quantum electrodynamics, a quantization scheme for electromagnetic fields in non-homogeneous, dispersive, and lossy media. To capture both molecular and dielectric contributions, our formulation incorporates two baths: molecular vibrations and a dielectric-photonic continuum that generates polaritons. This formulation is then transformed into a numerically tractable form that can be naturally combined with methods such as the pseudomode approach or the hierarchical equations of motion. Using a molecule above a plasmonic surface as an example, we show that the framework captures accurate dynamics across light–matter coupling regimes, thereby providing a powerful tool for investigating polariton-mediated electron transfer.