Resonance Theory of Vibrational Strong Couplings in Polariton Chemistry

In this work, we present a new theoretical explanation of the resonance vibrational strong coupling (VSC) regime in polariton chemistry. Coupling molecular vibrations and the cavity photonic excitation has experimentally demonstrated to strongly influence the ground state kinetics of a chemical reaction. Our theoretical results suggest that the VSC kinetics modification originates from the non-Markovian behavior of the cavity radiation mode when coupling to the molecule, leading to the dynamical caging of the reaction coordinate and the suppression of chemical reaction rate for a given range of photon frequency that is close to the barrier frequency. Further, we use a simple analytical non-Markovian rate theory to describe a single molecular system coupled to a radiation mode in an optical cavity. We demonstrate the accuracy of the rate theory by performing a numerical calculation in a one-dimensional model molecular system coupled to the cavity. Our simulations and analytical theory demonstrate the importance of dynamical effects in VSC polaritonic chemistry.