Abstract
We present a non-Hermitian formulation of the polaritonic structure of azobenzene strongly coupled to a photonic mode that explicitly accounts for the fleeting nature of the photon-molecule interaction. This formalism reveals that the polaritonic non-adiabatic couplings that facilitate the cis-trans isomerization can be dramatically modified by the inclusion of the photonic dissipation into the polaritonic Hamiltonian. We perform Fewest-Switches Surface Hopping dynamics on the surfaces that derive from our non-Hermitian formalism and find that the polaritonic isomerization rates are strongly suppressed for moderate to large photon dissipation rates. These findings highlight the important role that the nite lifetime of photonic degrees of freedom play in polaritonic chemistry.