Melting and Shock Hugoniot states of beryllium, iron, and silicate materials from first principles simulations

The equation of state (EoS) of materials is one of the most important components in the description of properties of matter at high pressure. Materials like beryllium are subject to extreme conditions when used as ablators in inertial confinement fusion experiments, while magnesium oxide (MgO) is present at extreme conditions in the mantle of rocky planets. Their phase diagrams share many similarities and understanding the role of anharmonicities in the lattice is crucial to determine how its instability is modified by temperature, especially near the melting point. In addition, being able to determine the Hugoniot states from the EoS obtained from first-principles allows a direct comparison with shock experiments and places constraints on the phase boundaries, which helps interpreting the measurements and guiding the experiments. Here, we present the Hugoniot curves, melting lines, and solid-solid phase boundaries of Be [1], MgO [2], MgSiO₃ [3], H₂O-silicates mixtures [4], Mg [5,6], and Fe obtained from density functional theory molecular dynamics simulations. Our comparison with experiments, when available, shows very good agreement.