Dynamic coexistence of several phaselike forms, a solid, microcrytalline 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 mean-field model showing that the observed behavior is possible if (a) the core and surface both undergo finite-system analogs of first-order transitions with overlapping coexistence regions and (b) the mode-softening defects of the core exhibit an attractive interaction with the vacancy-floater pairs on the surface.

• Received 13 August 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.3987