Unravelling the peculiar nucleation mechanisms for non-ideal binary mixtures with atomistic simulations.

Recent experiments reveal unusual nucleation behavior for seemingly simple mixtures that cannot be described by the classical theory. Molecular simulations using a combination of aggregation-volume-bias Monte Carlo, umbrella sampling, and histogram reweighting methods were carried out to study the nucleation events involved in the water/ethanol, water/n-nonane, and n-nonane/ethanol mixtures. These simulations reproduced their different nonideal behaviors observed by the experiments. Furthermore, the finding of their strikingly distinct mechanisms, as implied from the calculated free-energy maps, challenges the current theoretical description of this phenomenon.