Density dependence of the velocity of sound in expanded liquid mercury by a large-scale molecular-dynamics simulation

The density dependence of the velocity of sound in liquid mercury along the liquid-vapour coexistence curve is investigated by a large-scale molecular-dynamics simulation using the effective pair potential derived from the experimental structure factor by the inverse method. The velocities of sound obtained from the calculated dispersion curves for three thermodynamic states are in very good agreement with the experiments and the density dependence of the velocity of sound changes at 9 g/cm(3), where the metal-non-metal transition occurs. We show that the repulsive part of the effective pair potential plays a crucial role in the density dependence of the velocity of sound in liquid mercury. (C) 1999 Elsevier Science B.V. All rights reserved.