Ab InitioMolecular Dynamics of Metallic Hydrogen at High Densities

The fully ionized (metallic) hydrogen plasma is studied by ab initio molecular dynamics simulations, for classical protons and fully degenerate electrons, in the strong coupling regime of the protons. The calculated ion-electron pair distribution function signals the breakdown of linear screening with decreasing density while the melting temperature of the proton crystal drops rapidly. The simulations reveal the remarkable persistence of a weakly damped high-frequency ion acoustic mode, even under conditions of strong electron screening.