title: Demixing of hydrogen and helium at megabar pressures.
abstract: We present results of ab initio finite-temperature density functional theory molecular dynamics simulations for fluid hydrogen-helium mixtures at megabar pressures. The location of the miscibility gap is derived from the equation of state data. We find a close relation between hydrogen-helium phase separation and the continuous nonmetal-to-metal transition in hydrogen. Our calculations predict that demixing of hydrogen and helium occurs in Saturn and probably also in Jupiter. These results will have a strong impact on interior models of giant solar and extrasolar planets.
authors.affiliation: Institut für Physik, Universität Rostock, D-18051 Rostock, Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: Lorenzen
authors.forename: Bastian
authors.initials: B
authors.lastname: Holst
authors.forename: Ronald
authors.initials: R
authors.lastname: Redmer