Simulation of the photodynamics of azobenzene on its rst excited state: comparison of full multiple spawning and surface hopping treatments

We have run Full Multiple Spawning simulations for the cis -> trans and trans -> cis photoisomerization of azobenzene by n -> pi* excitation. The quantum mechanical description of the nonadiabatic dynamics has been compared with a previous semiclassical treatment based on Surface Hopping. We concentrate on the dynamical effects that determine the photoisomerization quantum yields, namely the rate of radiationless electronic relaxation and the inertia of the motion along the reaction coordinate. The quantal and semiclassical results are in good general agreement, thus confirming our previous analysis of the photodynamics. The Surface Hopping method slightly overestimates the rate of excited state decay, which in this case leads to compute lower quantum yields.