PHASE COEXISTENCE IN CLUSTERS

An analytical cluster wetting model is developed, based on minimizatio n of an expression for the free energy, for solid-liquid equilibrium c oexistence states in clusters. For given materials' characteristic int erfacial energies of the solid and liquid phases, the model relates th e fraction of the solid-phase area wetted by the liquid to the volume fraction of the two phases. Equilibrium coexistence states with nonwet ting, partial wetting, and complete wetting geometries, and their depe ndence on materials' properties and conditions of the system, are inve stigated. Analyses of molecular dynamics simulations of equilibrium so lid-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 mo del and experimental data.