MULTIPLE PHASE COEXISTENCE IN FINITE SYSTEMS

Dynamic coexistence of several phaselike forms, a solid, microcrystall ine phase, a homogeneously melted phase, and phases exhibiting a solid core and a melted surface, is found in isothermal molecular-dynamics simulations of magic-number rare-gas clusters. We present a theoretica l model for the equilibrium and dynamics of phases of small systems th at incorporates homogeneous and heterogeneous phases and gives necessa ry conditions for the material parameters if a cluster is to exhibit t he observed multiple-phase behavior.