, such that the reaction coordinate R becomes trapped in a narrow "solvent cage" on the barrier top. 396 At longer times, the bath relaxations of Ĥsb (Eq. 193) allow the R to move away from the barrier top, but at shorter times, the reaction coordinate R oscillates within the cavity-induced "solvent" cage. The trajectory recrosses the dividing surface (R ‡ = 0) many times, resulting in oscillations of κ(t) at a short time and with a small plateau value of κ(t) at t p . Similar dynamical caging effects from the solvent have been extensively studied in simple organic reactions (S N 1 and S N 2) and enzymatic reactions, where the solvent dynamics significantly influence the reaction rate constant. Here, the cavity photonic coordinate q c acts like a "solvent coordinate", and for strong couplings between q c and R, the system exhibits the dynamical caging effect which effectively slows down the reaction rate constant.