Surface melting-driven hydrogen absorption for high-pressure polyhydride synthesis.

ABSTRACT: The synthesis of new polyhydrides with high superconducting T_c is challenging owing to the high pressures and temperatures required. In this study, we used machine-learning potential molecular dynamics simulations to investigate the initial stage of polyhydride formation in calcium hydrides. Upon contact with high-pressure H₂, the surface of CaH₂ melts, leading to CaH₄ formation. This surface melting proceeds via CaH₄ liquid phase as an intermediate state. High pressure reduces not only the hydrogenation (CaH₂(s) + H₂(l) ↔ CaH₄(s)) enthalpy but also the enthalpy for liquid polyhydride formation (CaH₂(s) + H₂(l) ↔ CaH₄(l)). Consequently, this surface melting proces

SUBMITTER: Sato R 

PROVIDER: S-EPMC12146707 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature