A numerical study of the freezing behavior of an unsupported nanometer-sized Au droplet

Molecular dynamics calculations have been employed to simulate the freezing transition of an unsupported nanometer-sized Au droplet with a radius of about 3 nm. The freezing point was initially determined by gradually decreasing the droplet temperature by the stochastic Nosè thermostat. A realistic cooling process was then simulated starting from a liquid Au droplet slightly above the freezing point and employing a He gas collisional thermostat. Freezing nucleates at the droplet surface and is mediated by coalescence processes involving small clusters of solid-like atoms.