Transition events in butane simulations: Similarities across models

A spectrum of simulations was used to study molecular transition events in butane, which is the simplest alkane with a dihedral degree of freedom. The all-atom butane was studied in explicit water and acetic acid. The butane event-duration distributions and reaction-coordinate speed profiles were compared with those for one dimensional stochastic systems with white and colored noise. The distribution of transition event durations appeared to be universal across dynamics, solvent and potential type. The reaction coordinate speed profiles of butane transitions also displayed an accelerating trend.