The HTC model, Eq. ( ), accounts well for the main spectroscopic observations: The formation of hibride molecule/cavity-photon states that appear as a Rabi-split signal in the linear optical response of such systems as well as the characteristc dependence of the splitting, , on the numebr of molecules N (g characterizing the coupling between individial molecules and the cavity photon). The implication for the nuclear dynamics following such excitations has been discussed by several groups, leading to interesting predictions about the possible implication of strong coupling to a cavity mode on the standard Born-Oppenheimer (BO) picture of molecular nuclear dynamics. Arguments involving timescale speration between fast (electronic and cavity modes) and slow (vibrational) motions have led Spano, and later Herrera and Spano 14 to suggest that in the large molecular number limit, the nuclear potential surface associated with a polariton state is similar (up to deviations of order ) to the ground state potential surface, essentially implying vibronic decoupling with strong implications for subsequent interstate electronic transitions including electron transfer processes. Later theoretical studies have indeed confirmed the existence of vibronic decoupling, however in a restrictive form: provided that the Rabi splitting is large relative to the reorganization energy associated with the vibronic coupling. It has been suggested that such vibronic decoupling may have dramatic consequences for photophysical and photochemical processes initiated by polariton excitation. Another effect stems from the polariton shift, which can place the excitation energy closer or further away from reactive channels. Experimenhtally, predictions based on vibronic (or polaron) decoupling have not yet been verified experimentally, while effects associated with polaritonic energy shift have been observed by several workers. Further efforts to bridge between theory and experiments need to consider some shortcomings of the HTC mode as usually applied: First, while the model of Eq. ( ) considers a single (undamped) cavity mode, assuming near resonance between the molecular electronic transition and this modes, realistic cavity involves many modes whose dynamics should reflect also the way by which the external field interacts with †