Viscosity of liquid iron under high pressure and high temperature: Equilibrium and nonequilibrium molecular dynamics simulation studies

Abstract

Using classical molecular dynamics simulations together with a many-body embedded atom model (EAM) potential, we calculate the viscosity of liquid iron under high temperature and high pressure. We show that this EAM potential, in addition to reproducing experimental data on the structure of liquid iron at high pressure, accurately predicts the shear viscosity of liquid iron. We carefully assess the validity of our results, obtained from equilibrium molecular dynamics simulations as well as from nonequilibrium molecular dynamics simulations. Our estimates for the viscosity are shown to be in good agreement with those obtained from ab initio molecular dynamics simulations. This demonstrates that the EAM potential accurately describes both the thermodynamic and transport properties of liquid iron under extreme conditions and provides a satisfactory alternative to ab initio molecular dynamics simulations for large-scale simulations.