Challenges for excited states and dynamics in the presence of environment

The accurate description of excited states and its dynamics of molecules in the presence of an environment is a very challenging task because it requires, at least i) an appropriate description of the interactions between the chromophore and the environment, and ii) the calculation of the vibrational motion of the whole system. For the former, it is common to describe the environment either by quantum mechanics/continuum or quantum mechanics/molecular mechanics models. For the second, vibrational sampling can be described with Wigner sampling or with molecular dynamics. Several examples will be first shown to illustrate how different models can dramatically affect the excited states energies and other properties of the molecule. In the case of flexible molecules and in order to perform non-adiabatic dynamics, the situation is even more complex, as Wigner distributions cannot be used as initial conditions and molecular dynamics is not suitable to describe large amplitude motions correctly. Surface-hopping simulations using our local code SHARC for non-adiabatic dynamics including spin-orbit couplings will be shown on a transition metal complex in solution.