which is also supported by the HEOM results (blue open circles). If one hypothesizes that an unknown mechanism forces the upper or lower vibrational polariton states to be a "gateway of VSC polaritonic chemical reactions" , then the activation free energy change should shift linearly with Ω R . On the other hand, the experimental results demonstrate the nonlinearity of the reaction barrier . Our current theory (Eq. 41) indicates that the nonlinear increase of "effective ∆(∆G ‡ )" in Eq. 50 when increasing Ω R is due to the cavity promotion of the |ν L → |ν L transition, and more specifically, the effective ∆(∆G ‡ ) scales with