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arXiv · 2209.00658

Stable solid molecular hydrogen above 900K from a machine-learned potential trained with diffusion Quantum Monte Carlo

Hongwei Niu·Yubo Yang·Scott Jensen·Markus Holzmann·Carlo Pierleoni·David M. Ceperley
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Abstract

We survey the phase diagram of high-pressure molecular hydrogen with path integral molecular dynamics using a machine-learned interatomic potential trained with Quantum Monte Carlo forces and energies. Besides the HCP and C2/c-24 phases, we find two new stable phases both with molecular centers in the Fmmm-4 structure, separated by a molecular orientation transition with temperature. The high temperature isotropic Fmmm-4 phase has a reentrant melting line with a maximum at higher temperature (1450K at 150GPa) than previously estimated and crosses the liquid-liquid transition line around 1200K and 200GPa.

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Hongwei Niu, Yubo Yang, Scott Jensen, Markus Holzmann, Carlo Pierleoni, David M. Ceperley. 2022-09-01. Stable solid molecular hydrogen above 900K from a machine-learned potential trained with diffusion Quantum Monte Carlo. https://doi.org/10.1103/physrevlett.130.076102

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