Poster: Resonance Theory of Vibrational Polariton Chemistry

We perform numerically exact quantum dynamics simulations using the hierarchical equation of motion (HEOM) approach to investigate the resonance modification of chemical reaction rate constants due to the vibrational strong coupling (VSC) in polariton chemistry. The results reveal that the cavity mode acts like a ``rate-promoting vibrational mode" that enhances the ground state chemical reaction rate constant when the cavity mode frequency matches the vibrational transition frequency. The VSC-modified rate constant will first increase quadratically, then quickly saturate and decay as the Rabi splitting $Omega_R$ increases. When changing the cavity lifetime $ au_c$ from the lossy to the lossless limit, the numerical results show there will be a turnover of the rate constant. With given $Omega_R$, the resonance enhancement of VSC rate is proportional to $ au_c$ in the lossy limit of $ au_c ll 1 / Omega_R$, and to $1 / au_c$ in the lossless limit of $ au_c gg 1 / Omega_R$. We further present an analytic rate theory based on Fermi's golden rule to explain the observed behaviors of VSC rates, including the sharp resonance peak and origin of its broadening, the effects of $Omega_R$ and $ au_c$, resonance condition at the normal incidence, etc. To the best of our knowledge, this is the first analytic theory that clearly illustrates the reaction mechanism under VSC modifications, and is able to explain the sharp resonance behavior of the VSC-modified rate profile with quantitative accuracy.