Abstract :

Metal nano-clusters (NCs) exhibit unique and interesting thermodynamic behaviour as compared to single molecule as well as bulk materials. Classical Molecular Dynamics (MD) simulations with Modified Embedded Atom Method (MEAM) model has been carried out in order to study the melting phenomena of Silver (Ag) NCs. Two NCs consisting of 108 and 1372 Ag atoms are chosen. The melting point temperature of these NCs has been estimated from various analyses techniques, such as: variation of potential energy per atom, mean square displacement of atoms, self-diffusion coefficients of atoms with temperature. The jump in the data corresponds to phase transition marking the starting of melting phenomena. From all these analyses, the melting point temperature of 108 atoms NC is found to be 380K and that of 1372 atoms NC is 730K, where the phase transition is marked. It is concluded that the melting point temperature of NCs are much smaller than the bulk (~1200K) and also the melting point of NCs are size dependent. The smaller the size, smaller is the melting point temperature.