Fast prediction of the melting of FeHx in planetary interiors

Abstract

FeH${}_x$ is a crucial mineral in geophysics, but its melting properties remain poorly understood at high pressures. In this Short Communication, we introduce a simple analytical model to access the solid–liquid boundary of FeH${}_x$ with minimal time and cost. Inspired by the work-heat equivalence principle, our model allows geophysicists to effectively exploit available ab initio resources to directly deduce the melting temperature of FeH${}_x$ from its equation of state. The obtained results agree quantitatively with cutting-edge atomistic simulations throughout a wide range of hydrogen content and hydrostatic pressure. Therefore, our analyses would have implications for elucidating the internal dynamics of rocky worlds within and beyond our Solar System.