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Title: Communication: Dynamical and structural analyses of solid hydrogen under vapor pressure

Nuclear quantum effects play a dominant role in determining the phase diagram of H{sub 2}. With a recently developed quantum molecular dynamics simulation method, we examine dynamical and structural characters of solid H{sub 2} under vapor pressure, demonstrating the difference from liquid and high-pressure solid H{sub 2}. While stable hexagonal close-packed lattice structures are reproduced with reasonable lattice phonon frequencies, the most stable adjacent configuration exhibits a zigzag structure, in contrast with the T-shape liquid configuration. The periodic angular distributions of H{sub 2} molecules indicate that molecules are not a completely free rotor in the vapor-pressure solid reflecting asymmetric potentials from surrounding molecules on adjacent lattice sites. Discrete jumps of librational and H–H vibrational frequencies as well as H–H bond length caused by structural rearrangements under vapor pressure effectively discriminate the liquid and solid phases. The obtained dynamical and structural information of the vapor-pressure H{sub 2} solid will be useful in monitoring thermodynamic states of condensed hydrogens.
Authors:
 [1] ;  [2] ;  [1]
  1. Department of Chemistry, Kyoto University, Kyoto 606-8502 (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
22493187
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 97 MATHEMATICAL METHODS AND COMPUTING; ANGULAR DISTRIBUTION; BOND LENGTHS; HCP LATTICES; HYDROGEN; LIQUIDS; MOLECULAR DYNAMICS METHOD; MOLECULES; MONITORING; PHASE DIAGRAMS; PHONONS; SIMULATION; SOLIDS; VAPOR PRESSURE