Investigation of thermal behavior of graphite-supported Ag nanoclusters of different sizes using molecular dynamics simulations

Abstract

Thermal behaviors of Ag nanoclusters with 38, 108 and 256 atoms supported on static graphite bilayer substrate were investigated using molecular dynamics (MD) simulations. The many body quantum Sutton–Chen (QSC) potential was used to describe the Ag–Ag interactions, also, the Lennard–Jones (LJ) 12–6 potential was applied for Ag–graphite interactions. Nanoclusters were simulated for heating and cooling in the range of 100–1700K in the canonical ensemble. The potential energy, specific heat capacity, density profile, deformation parameter and self-diffusion coefficient were calculated at different temperatures. Results show that melting temperatures are higher than that for free Ag nanoclusters of similar size and structure. Comparison of the potential curves in heating and cooling for three nanoclusters show that the hysteresis decreases when the cluster size decreases. Also, irreversibility of the structural changes relative to temperature, Flattening of nanocluster on the graphite surface and wetting were observed using the density profiles and deformation parameters.