Ab Initio Investigation of a Possible Liquid-Liquid Phase Transition in MgSiO3 at Megabar Pressures

Abstract

We perform density functional molecular dynamics simulations of liquid and solid MgSiO3 in the pressure range of 120-1600 GPa and for temperatures up to 20000 K in order to provide new insight into the nature of the liquid-liquid phase transition that was recently predicted on the basis of decaying laser shock wave experiments [Phys. Rev. Lett. 108 (2012) 065701]. However, our simulations did not show any signature of a phase transition in the liquid phase. We derive the equation of state for the liquid and solid phases and compute the shock Hugoniot curves. We discuss different thermodynamic functions and by explore alternative interpretations of the experimental findings.

15 pages, 7 figures, 2 tables, 29 references

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• A Massive Core in Jupiter Predicted From First-Principles Simulations
• FPEOS: A First-Principles Equation of State Table of Deuterium for Inertial Confinement Fusion Applications
• Rocky core solubility in Jupiter and giant exoplanets
• Phase separation in hydrogen-helium mixtures at Mbar pressures
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Cited by in corpus (4)

• Decaying shock studies of phase transitions in MgOSiO2 systems: implications for the Super-Earths interiors
• Ab Initio Simulations of Hot, Dense Methane During Shock Experiments
• Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Warm, Dense MgSiO${}_3$
• High Pressure Phase Diagram of Beryllium from \emph{Ab Initio} Free Energy Calculations