Lattice stability and high-pressure melting mechanism of dense hydrogen up to 1.5 TPa
- Inst. of Fluid Physics, Sichuan (China); Cornell Univ., Ithaca, NY (United States)
- Cornell Univ., Ithaca, NY (United States)
- Inst. of Fluid Physics, Sichuan (China)
Lattice stability and metastability, as well as melting, are vital features of the physics and chemistry of dense hydrogen. Using ab initio molecular dynamics (AIMD), the classical superheating limit and melting line of metallic hydrogen are investigated up to 1.5 TPa. The computations show that the classical superheating degree is about 100 K, and the classical melting curve becomes flat at a level of 350 K when beyond 500 GPa. This data allows us to estimate the well depth and the potential barriers that must be overcome when the crystal melts. Inclusion of nuclear quantum effects (NQE) using path integral molecular dynamics (PIMD) predicts that both superheating limit and melting temperature are lowered to below room temperature, but the latter never reaches absolute zero. Detailed analysis indicates that the melting is thermally activated, rather than driven by pure zero-point motion (ZPM). This argument was further supported by extensive PIMD simulations, demonstrating the stability of Fddd structure against liquefaction at low temperatures.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Energy Frontier Research in Extreme Environments (EFree)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0001057; DESC0001057
- OSTI ID:
- 1371031
- Alternate ID(s):
- OSTI ID: 1213932
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 92, Issue 10; Related Information: EFree partners with Carnegie Institution of Washington (lead); California Institute of Technology; Colorado School of Mines; Cornell University; Lehigh University; Pennsylvania State University; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Optical properties of dense lithium in electride phases by first-principles calculations
|
journal | March 2018 |
Predicted reentrant melting of dense hydrogen at ultra-high pressures
|
journal | November 2016 |
Thermodynamic anomalies and three distinct liquid-liquid transitions in warm dense liquid hydrogen
|
journal | October 2019 |
Simple thermodynamic model for the hydrogen phase diagram
|
journal | March 2017 |
A simple thermodynamic model for the hydrogen phase diagram | text | January 2017 |
The quantum nature of hydrogen | preprint | January 2018 |
Similar Records
Nuclear quantum effects on the high pressure melting of dense lithium
Polymorphism and melt in high-pressure tantalum. II. Orthorhombic phases