First-principles study of the solid solution of hydrogen in lanthanum

Journal Article · Thu Sep 01 04:00:00 EDT 2011 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.84.094122· OSTI ID:21596882

Schoellhammer, Gunther; Herzig, Peter; Wolf, Walter; Vajda, Peter; Yvon, Klaus ^[1]

---

1. Institut fr Physikalische Chemie, Universitt Wien, Whringer Strasse, A-1090 Vienna (Austria)

Results from first-principles investigations of the energetical, structural, electronic, and vibrational properties of model structures probing the metal-rich region of the lanthanum-hydrogen system, i.e., the region of the solid solution of hydrogen in lanthanum, are presented. We have studied the site preference and the ordering tendency of hydrogen atoms interstitially bonded in close-packed lanthanum. Spatially separated hydrogen atoms have turned out to exhibit an energetical preference for the occupation of octahedral interstitial sites at low temperature. Indications for a reversal of the site preference in favor of the occupation of tetrahedral interstitial sites at elevated temperature have been found. Linear arrangements consisting of pairs of octahedrally and/or tetrahedrally coordinated hydrogen atoms collinearly bonded to a central lanthanum atom have turned out to be energetically favorable structure elements. Further stabilization is achieved if such hydrogen pairs are in turn linked together so that extended chains of La-H bonds are formed. Pair formation and chain linking counteract the energetical preference for octahedral coordination observed for separated hydrogen atoms.

• OSTI ID: 21596882
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 9 Vol. 84; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
CHAINS
COMPUTERIZED SIMULATION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISPERSIONS
ELEMENTS
HOMOGENEOUS MIXTURES
HYDROGEN ADDITIONS
INTERSTITIALS
LANTHANUM
METALS
MIXTURES
OCCUPATIONS
POINT DEFECTS
RARE EARTHS
SIMULATION
SOLID SOLUTIONS
SOLUTIONS
STABILIZATION
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K