Molecular dynamics study of liquid iron under high pressure and high temperature

Abstract

Unlike ab initio calculations, classical potentials in molecular dynamics (MD) allow the treatment of very large atomic systems. However, the quality of the potentials has to be carefully assessed, making the evaluation of the models important. By means of MD simulations, we have studied the properties of liquid iron (Fe) with an embedded-atom method (EAM) under extreme pressure-temperature conditions, to resemble the conditions found in the Earth's outer core. The model used for the MD simulations is demonstrated to reproduce recent experimentally determined structure factor calculations to the highest pressure of $58\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. The calculations of densities and diffusion parameters at the various temperatures and pressures agree well with first-principles calculations. The results indicate the model's validity for the physical description of liquid iron at extreme conditions.