Abstract
Recent experiments have demonstrated remarkable mode-selective reactivities by coupling molecular vibrations with vacuum fluctuations inside an optical cavity. The fundamental mechanism behind such effects, on the other hand, remains elusive. In this work, we theoretically demonstrate the basic principle of how cavity photon frequency can be tuned to achieve mode-selective reactivities. We find that the non-Markovian nature of the radiation mode leads to a cavity frequency-dependent dynamical caging effect of a reaction coordinate, resulting in a suppression of the rate constant. In the presence of multiple competitive reactions, it is possible to preferentially cage a reaction coordinate when the barrier frequencies for competing reaction paths are different. Our theoretical results illustrate the cavity-induced mode-selective chemistry through polaritonic vibrational-strong couplings, revealing the fundamental mechanism for changing chemical selectivities through cavity quantum electrodynamics.