Appraisal of the realistic accuracy of molecular dynamics of high-pressure hydrogen

Molecular dynamics (MD) is a powerful method for studying the behaviour of materials at high temperature. In practice, however, its effectiveness in representing real systems is limited by the accuracy of the forces, finite size effects, quantization and equilibration methods. In this paper, we repo...

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Bibliographic Details
Published inCogent physics Vol. 2; no. 1; p. 1049477
Main Authors Ackland, Graeme J., Magdău, Ioan B.
Format Journal Article
LanguageEnglish
Published Abingdon Cogent 31.12.2015
Taylor & Francis Ltd
Subjects
density functional theory
exchange-correlation
high pressure
High temperature
hydrogen
lattice dynamics
metallization
Molecular dynamics
Molecular structure
path integral
Size effects
System effectiveness
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Summary:Molecular dynamics (MD) is a powerful method for studying the behaviour of materials at high temperature. In practice, however, its effectiveness in representing real systems is limited by the accuracy of the forces, finite size effects, quantization and equilibration methods. In this paper, we report and discuss some calculations carried out using MD on high-pressure hydrogen, reviewing a number of sources of error, of which the neglect of zero-point vibrations is quantitatively the largest. We show that simulations using ab initio MD with the PBE functional predict a large stability field for the molecular Cmca4 structure at pressures just above those achieved in current experiments above the stability range of the mixed molecular layered Phase IV. However, the various errors in the simulation all point towards a much smaller stability range, and the likelihood of a non-molecular phase based on low-coordination networks or chains of atoms.
ISSN:2331-1940
2331-1940
DOI:10.1080/23311940.2015.1049477