Parameterized Molecular Cavity Quantum Electrodynamics Approach to Simulate van der Waals Interactions

The strong coupling between light and matter inside optical cavities has emerged as a strategy to modify the chemical and physical properties of materials. In this work, we explore the performance of the recently developed parameterized quantum electrodynamics (pQED) approach based on time-dependent density functional theory (TDDFT) for non-covalently interacting systems, including van der Waals and hydrogen bonding interactions. We find that the pQED-TDDFT approach accurately reproduces the cavity-modified potential energy surfaces of the polaritonic ground state, compared with high-level QED coupled-cluster and state-of-the-art QED density functional theory results. By computing the ground-state density difference, we show that the dispersion-energy modifications are due to electronic density redistribution inside the cavity.