where 𝜖 0 is the effective permittivity inside the cavity and 𝒱 is the cavity quantization volume. Each reaction coordinate 𝑅 𝑗 is coupled to its own local phonon bath described by Ĥ𝜈 . Each cavity mode qk couples to its independent bath {x k,𝜁 }, accounting for the cavity loss. The cavity modes {q k } couple to the dipole of each molecule 𝜇( R𝑗 ), where 𝜙 𝑗 is the relative angle between the dipole vector and the field polarization direction. Details of the Hamiltonian are provided in the Supplementary Material, Sec. I. Fig. presents a schematic illustration of the cavity dispersion relation in Eq. 2 (red dashed line). The molecular excitation dispersion (black dashed line) is insensitive to the incident angle and is a straight line, with energy ℏ𝜔 0 (see Eq. 7). These two dispersions hybridize due to the light-matter interactions, generating polariton dispersions (the upper and lower branches with solid curves) with the color coding indicating the character of the states, with purely photonic (red), purely vibrational (black), and hybridized (yellow to orange). Fig. presents a schematic illustration of the typical cavity detuning dependence of the rate constant modifications, with the highest intensity of the modification arising at the frequency when 𝜔 c = 𝜔 0 (resonance condition under normal incidence).