First-principles determination of the meltinbehaviour of hydrogen at high pressures

Abstract

This project aims to predict the melting behaviour of hydrogen up to pressures of 4 Mbar (400 GPa) from first principles coexistence simulations. In so doing we will be providing detailed information of the thermodynamics of hydrogen at extreme pressures, information that is crucial to further our understanding of matter at such conditions, and which will be essential for the development of geological models of the interior of the large gaseous planets in the solar system. Currently the melting line of hydrogen has been explored up to pressures of 1.5 Mbar, so its properties at higher pressures remains unexplored. In particular, theoretical predictions have suggested that, at higher pressures hydrogen could become a low- temperature metallic liquid or even a high-temperature superconductor, but it has been thus far impossible to confirm these predictions experimentally. With this project, we will provide new theoretical data that will complement the rather incomplete picture that we have at present about the behaviour of hydrogen at extreme conditions. Hopefully this will allow us to answer questions such as Does hydrogen become a liquid metal at low temperatures? Does it instead follow a continuous sequence of solid phases?, questions that are some of the most fundamental in condensed matter physics and materials science.