Evidence for surface melting in clusters made of double icosahedron units

We study the thermodynamics of small Lennard-Jones clusters (19 ⩽ N </ 34), from both molecular dynamics and Monte Carlo data, analysed with the multiple histogram method. In the case of the 29-atom, 32-atom and 34-atom clusters, there are several indications that a narrow range of internal energies exists where the cluster remains with a solid core and a liquid-like surface. We compare these results with the known surface melting in the Mackay icosahedron LJ55.