Then, the Condon approximation can the be applied to treat for photon-photon and photon-electron interactions. Duschinsky rotations and complex normal mode couplings are omitted as a way to account for quantum electrodynamical effects on the internal conversion mechanism. This allows for the vibronic and cavity based contributions to the rate constant to be effectively decoupled, at least to a degree. Therefore, the internal conversion rate constant within a cavity can be recast as :