Molecular-dynamic modeling of thermodynamic properties of the lunar Fe-S core

Abstract

The physical properties (density, modules of compression, heat capacity, and velocity of the P-waves) of the lunar Fe-S core are modeled with molecular dynamics and the Embedded Atom Model potential at 0–18 at % S content, temperatures up to 2500 K, and pressures up to 5 GPa. The thermodynamic calculations of the velocity of P-waves in the liquid lunar core are consistent with the interpreted results of seismic processing of the Apollo observations. According to calculations, the density of the liquid core may vary from 7.4 (pure liquid iron) to 6.75 (10 at % S at 1950 ± 50 K) g/cm3. This approach provides more reliable restrictions for the inner structure of the Moon.