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arXiv · 1610.01967

High-Pressure Hydrogen Sulfide by Diffusion Quantum Monte Carlo

Sam Azadi·Thomas D. Kühne
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Abstract

We use the diffusion quantum Monte Carlo to revisit the enthalpy-pressure phase diagram of the various products from the different proposed decompositions of H$_2$S at pressures above 150~GPa. Our results entails a revision of the ground-state enthalpy-pressure phase diagram. Specifically, we find that the C2/c HS$_2$ structure 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 I4$_1$/amd HS structure over the whole pressure range from 150 to 400 GPa. Moreover, we predict that the Im-3m phase is the most likely candidate for H$_3$S, which is consistent with recent experimental x-ray diffraction measurements.

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Sam Azadi, Thomas D. Kühne. 2016-10-06. High-Pressure Hydrogen Sulfide by Diffusion Quantum Monte Carlo. https://doi.org/10.1063/1.4976836

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