Static and dynamic properties of liquid Au were studied via molecular-dynamics and Monte Carlo simulations, using a many-body potential based upon effective-medium theory. In order to address the temperature dependence of the self-diffusion coefficient (linear, exponential, and other dependences were proposed in the literature), simulations were performed in a dense temperature mesh up to the boiling point (3080K). The liquid structure at various temperatures was described in terms of the pair distribution function, which was compared with X-ray data. Computed thermodynamic properties were in good agreement with experiment. Dynamic properties were represented by the velocity correlation function and self-diffusion coefficients of high accuracy. The temperature dependence of the diffusivity was qualitatively compared with several theoretical model predictions. A proportionality of the diffusion coefficient to the square of the temperature was found, in agreement with microgravity experiments on other non-simple liquids. An analysis was made of atomic trajectories and the velocity correlation function at various temperatures, to provide physical arguments for and against different diffusion models in liquids. One of the results of this study was that it opposed diffusion processes with a single non-zero activation energy of, e.g., Arrhenius type.

Simulations of Atomic Structure, Dynamics, and Self-Diffusion in Liquid Au. A.Bogicevic, L.B.Hansen, B.I.Lundqvist: Physical Review E, 1997, 55[5A], 5535-45