Melting of small gold particles: Mechanism and size effects

We present extensive molecular-dynamics simulations of small gold particles of N=100--900 atoms. We use a many-body interatomic potential of proven accuracy for gold surfaces. Structural properties are determined with various annealing strategies. Our results provide for the first time a microscopic description of the melting transition of metal clusters, revealing in particular the formation of a liquid skin as precursor effect for N>350. The experimentally observed sharp decrease of the melting temperature with decreasing size is recovered. Implications for larger sizes, as well as for other metals, are discussed.