Melting properties of noble metal clusters

The melting behaviors of noble metal clusters Ag-55, Cu-55 and Au-55 have b een investigated by molecular-dynamics simulations with an empirical many-b ody potential. Comparing with bulk materials, the enthalpy changes DeltaH(m ) during solid-liquid transitions of clusters drop remarkably as well as th e melting temperatures T-m, which an customarily due to the size confinemen t for clusters. Furthermore, the effect of limited size on melting-like tra nsition is quite different among the three clusters. Gold cluster has been found to suffer the most from the size confinement effect, which can be ill ustrated 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) 2 000 Elsevier Science Ltd. All rights reserved.