ReaxFF-based nonadiabatic dynamics method for azobenzene derivatives

ReaxFF reactive force fields have been parametrized for the ground and first excited state of azobenzene and its derivatives. In addition, an extended set of ab initio reference data ensures wide applicability, including to azosystems in complex environments. Based on the optimized force fields, nonadiabatic surface hopping simulations produce photoisomerization quantum yields and decay times of azobenzene, both in the gas-phase and in n-hexane solution, in reasonable agreement with higher level theory and experiment. The simulation of the ring-opening of cyclobutene triggered by the photoisomerization of azobenzene in a macrocycle highlights the advantages of a reactive force field model.