title: High-pressure hydrogen sulfide by diffusion quantum Monte Carlo.
abstract: We revisit the enthalpy-pressure phase diagram of the various products from the different proposed decompositions of H2S at pressures above 150 GPa by means of accurate diffusion Monte Carlo simulations. Our results entail a revision of the ground-state enthalpy-pressure phase diagram. Specifically, we find that the C2/c HS2structure is persistent up to 440 GPa before undergoing a phase transition into the C2/m phase. Contrary to density functional theory, our calculations suggest that the C2/m phase of HS is more stable than the I41/amd HS structure over the whole pressure range from 150 to 400 GPa. More importantly, we predict that the Im-3m phase is the most likely candidate for H3S, which is consistent with recent experimental x-ray diffraction measurements.
authors.affiliation: Department of Materials Science, Royal School of Mines, Thomas Young Center, London Centre for Nanotechnology, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Sam
authors.identifier: 0000000210404645
authors.initials: S
authors.lastname: Azadi
authors.affiliation: Dynamics of Condensed Matter, Department of Chemistry, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany and Paderborn Center for Parallel Computing and Institute for Lightweight Design with Hybrid Systems, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Kühne