Melting properties of noble metal clusters

The melting behaviors of noble metal clusters Ag55, Cu55 and Au55 have been investigated by molecular-dynamics simulations with an empirical many-body potential. Comparing with bulk materials, the enthalpy changes ΔHm during solid–liquid transitions of clusters drop remarkably as well as the melting temperatures Tm, which are 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 Tm and Hm. The dependence of size confinement effect on substance can be attributed to the characteristic long-range correlation of interaction potentials.