The Influence of High Pressure and Temperature on Transport Properties of Liquid Magnesium Oxide

This work provides insights into the effects of both temperature and pressure on structure, dynamics, and diffusion mechanism in liquid magnesium oxide (MgO) systems. The Molecular Dynamics simulation (MDs) method and a kinetic approach are employed in this research. The structure of liquid MgO undergoes changes under compression, primarily consisting of the polyhedral units of MgO3, MgO4, and MgO5 at ambient pressure and MgO5 and MgO6 at high pressures up to 25 GPa. Meanwhile, the structure of liquid MgO is still composed of the polyhedral units of MgO3, MgO4, and MgO5 at different temperatures. The diffusion mechanism in liquid MgO involves the transition of the polyhedral units from MgOx to MgOx±1. We found that two factors contribute significantly to the diffusion process of the liquid MgO system including the mean square of transition dtr and the rate of transition rtr coefficient.