Static and dynamic properties of liquid lead computed by molecular dynamics.

Abstract

Using a six-center Lennard-Jones (12-6) pair potential, we modeled lead liquid at two different thermodynamic states by molecular-dynamics (MD) computations. While the static structure factor is found to agree with experiment at both states, the pressure is reproduced only for the lower temperature. Self-diffusion and shear viscosity are in reasonable agreement with experimental results. However, the thermal conductivity is predicted far too low. We emphasize the following points: (i) the chosen multiple-center pair potential has only three free parameters that were fitted by about ten test MD runs, each of which required only 3 min on a supercomputer; (ii) the production computations for the structure factor and the self-diffusion were carried out with 500 molecules, while the transport coefficients were obtained by runs with 32 molecules. Thus our findings stand in sharp contrast to recent calculations of Dzugutov, Larsson, and Ebbsj\"o [Phys. Rev. A 38, 3609 (1988)] who claimed that a seven-parameter pair potential and a very large number of particles are required to model liquid lead by MD computations.