  We use molecular dynamics simulations to study the melting of gold
icosahedral clusters of a few thousand atoms. We pay particular attention to
the behavior of surface atoms, and to the equilibrium shape of the cluster. We
find that although the surface of the cluster remains ordered up to the melting
T_m, the increasing mobility of vertex and edge atoms significantly soften the
surface structure, leading to inter- and intra-layer diffusion, and shrinking
of the average facet size, so that the average shape of the cluster is nearly
spherical at melting.
