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DOE OSTI · 2561243

High temperature melting of dense molecular hydrogen from machine-learning interatomic potentials trained on quantum Monte Carlo

Goswami, Shubhang [University of Illinois Urbana-Champaign, IL (United States); University of Illinois] (ORCID:0000000309638003)·Jensen, Scott [University of Illinois Urbana-Champaign, IL (United States)] (ORCID:0000000265762204)·Yang, Yubo [Flatiron Institute, New York, NY (United States); Hofstra University, Hempstead, NY (United States)] (ORCID:0000000288009426)·Holzmann, Markus [Univ. Grenoble Alpes (France)] (ORCID:0009000808032732)·Pierleoni, Carlo [University of L’Aquila (Italy)] (ORCID:0000000191883846)·Ceperley, David M. [University of Illinois Urbana-Champaign, IL (United States)] (ORCID:0000000150826271)
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Abstract

We present results and discuss methods for computing the melting temperature of dense molecular hydrogen using a machine learned model trained on quantum Monte Carlo data. In this newly trained model, we emphasize the importance of accurate total energies in the training. We integrate a two phase method for estimating the melting temperature with estimates from the Clausius–Clapeyron relation to provide a more accurate melting curve from the model. We make detailed predictions of the melting temperature, solid and liquid volumes, latent heat, and internal energy from 50 to 180 GPa for both classical hydrogen and quantum hydrogen. At pressures of roughly 173 GPa and 1635 K, we observe molecular dissociation in the liquid phase. Here, we compare with previous simulations and experimental measurements.

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08 HYDROGENHydrogenInteratomic potentialsMachine learningPhase transitionsThermodynamic properties

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Goswami, Shubhang [University of Illinois Urbana-Champaign, IL (United States); University of Illinois] (ORCID:0000000309638003), Jensen, Scott [University of Illinois Urbana-Champaign, IL (United States)] (ORCID:0000000265762204), Yang, Yubo [Flatiron Institute, New York, NY (United States); Hofstra University, Hempstead, NY (United States)] (ORCID:0000000288009426), Holzmann, Markus [Univ. Grenoble Alpes (France)] (ORCID:0009000808032732), Pierleoni, Carlo [University of L’Aquila (Italy)] (ORCID:0000000191883846), Ceperley, David M. [University of Illinois Urbana-Champaign, IL (United States)] (ORCID:0000000150826271). 2025-02-05. High temperature melting of dense molecular hydrogen from machine-learning interatomic potentials trained on quantum Monte Carlo. https://doi.org/10.1063/5.0250686

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