PHASE COEXISTENCE IN CLUSTERS

An analytical cluster wetting model is developed, based on minimization of an expression for the free energy, for solid-liquid equilibrium coexistence states in clusters. For given materials' characteristic interfacial energies of the solid and liquid phases, the model relates the fraction of the solid-phase area wetted by the liquid to the volume fraction of the two phases. Equilibrium coexistence states with nonwetting, partial wetting, and complete wetting geometries, and their dependence on materials' properties and conditions of the system, are investigated. Analyses of molecular dynamics simulations of equilibrium solid-liquid coexistence in (NaCl)(1000) and Ni-1289 clusters illustrate the higher self-wetting propensity of metals than that of ionic salts, and the results are in correspondence with the predictions of our model and experimental data.