To provide a microscopic mechanism of VSC-modified reactions, we hypothesize that the cavity modes enhance the transition from ground states to a vibrationally excited state manifold of the reactant, leading to an enhancement of the steady-state population of both the delocalized states on the reactant side and the excited states manifold on the product side (right well) {|𝜈 ′𝑗 R ⟩}, which then relax to the vibrational ground state manifold on the product side (right well), {|𝜈 𝑗 R ⟩}. For a single molecule strongly coupled to a single cavity mode, our numerical simulations have confirmed the validity of this hypothesis. The proposed reaction mechanism is represented below