THE DENSITY-DEPENDENCE OF THE VELOCITY OF SOUND IN EXPANDED LIQUID MERCURY STUDIED BY MEANS OF A LARGE-SCALE MOLECULAR-DYNAMICS SIMULATION

The density dependence of the velocity of sound in liquid mercury alon g the liquid-vapour coexistence curve is investigated by means of a la rge-scale molecular-dynamics simulation using the effective pair poten tial derived from the experimental structure factor by the inverse met hod. The resulting velocity of sound is in very good agreement with ex periment and its density dependence changes at 9 g cm(-3), at which po int the metal-nonmetal transition occurs. It is shown that the repulsi ve part of the effective pair potential plays a crucially important ro le in the density dependence of the velocity of sound in liquid mercur y.