Melting properties of noble metal clusters

The melting behaviors of noble metal clusters Ag-55, Cu-55 and Au-55 have been investigated by molecular-dynamics simulations with an empirical many-body potential. Comparing with bulk materials, the enthalpy changes DeltaH(m) during solid-liquid transitions of clusters drop remarkably as well as the melting temperatures T-m, which an customarily due to the size confinement for clusters. Furthermore, the effect of limited size on melting-like transition is quite different among the three clusters. Gold cluster has been found to suffer the most from the size confinement effect, which can be illustrated by a broad transition manner and drastic decrease of T-m and H-m. The dependence of size confinement effect on substance can be attributed to the characteristic long-range correlation of interaction potentials. (C) 2000 Elsevier Science Ltd. All rights reserved.