Based on these exact dynamics results, we further developed an analytic rate theory (Eq. 41), which is the central theoretical result of this work. Under the short cavity lifetime limit, τ c → 0, the rate reduces to an analytic answer in Eq. 44. We found that both the HEOM results and Fermi's Golden Rule (FGR) rate predict a resonant condition (Eq. 1) for the VSC-enhanced rate constant with a narrow width for the rate profile. The FGR rate theory predicts that the width of the VSCmodified rate profile is controlled by a convolution of two peaks: one with its width dictated by the nuclear vibrational broadening and the other with its width related to the cavity lifetime τ c . Both HEOM results and the FGR rate constants predict that the rate enhancement will scale non-linearly with respect to the light-matter coupling strength (Eq. 48), resulting in a nonlinear scaling of the effective free energy barrier change (Eq. 50) if one chooses to interpret the VSC rate change entirely due to the change of effective free energy barrier (which is not a reasonable interpretation but has been widely used in experimental papers 3 ). The current theory also predicts an interesting cavity lifetime dependence of the VSC modification on the rate constant. To the best of our knowledge, this is the first analytic rate theory to explain the adiabatic ground state chemical reaction modified by the VSC effect and to give a clear resonant behavior (Eq. 1). The interesting scaling of how the VSC rate constant will change by changing the light-matter coupling and cavity lifetime predicted by the current theory and the exact simulation encourages more experimental work to carefully study them, even with reactions that have already been reported.