Simulating nucleation of molecular solids

The activation free energy for nucleation of crystals from melts and solutions is described and simulated in a different way from traditional nucleation theory. For molecules at the surface of a nucleus, the unfavourable entropy of fusion outweighs the favourable enthalpy change. The free energy barrier to nucleation in pure melts is simulated from the entropy and enthalpy of fusion. By incorporating the unfavourable entropy of unmixing, nucleation from impure melts and solutions is also simulated. The nature of the metastable zone alters and its size is estimated.