In principle one could attempt to simulate spin crossovers with nonadiabatic molecular dynamics. However, the high computational costs for running the simulations limits their applicability to very fast reactions on the femtoor picosecond timescale, especially because the high sensitivity of reaction rates with respect to the potential-energy surface (PES) usually warrants expensive high-level electronic-structure methods. More importantly, many dynamics methods make use of classical trajectories and neglect quantum tunneling. It is thus more appropriate to turn to rate theories, which are well-suited to deal with reactions taking place on a slower timescale and can often incorporate quantum tunneling effects at least to some level of approximation.