Reaction-rate modifications for chemical processes have been reported due to strong coupling between reactant molecular vibrations and the cavity vacuum, however, no accepted mechanisms explain these observations. In this work, reaction-rate constants are extracted from evolving cavity transmission spectra, revealing resonant suppression of the intracavity reaction rate for alcoholysis of phenyl isocyanate with cyclohexanol. We observe up to an 80% suppression of the rate by tuning cavity modes to be resonant with the reactant isocyanate (NCO) stretch, the product carbonyl (CO) stretch, and cooperative reactant-solvent modes (CH). These results are explained using an open quantum system model that predicts resonant modifications of chemical reactivity via light-matter quantum coherences that depopulate vibrational excited states, suggesting fundamental links between chemistry and quantum science to be explored.
Added theoretical treatment and discussion