Strong hydrogen trapping at helium in tungsten: Density functional theory calculations

Journal Article · Thu Apr 01 00:00:00 EDT 2010 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.81.134112· OSTI ID:21366714

Jiang, B; Wan, F R; Geng, W T ^[1]

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1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

Using first-principles density functional theory calculations, we have investigated the interaction of H and He in W, a potential plasma-facing material in fusion reactors. Strong attraction is found between He and H due to a decreased electron density around He. In the vicinity of a substitutional He atom, the H choose to stay in the tetrahedral-, rather than octahedral-interstitial sites. The maximum number of H atoms that one substitutional He can trap is 12, despite a much smaller local open volume than a vacancy offers. The trapping energy to He for the first H is as large as -0.96 eV. Such a strong attraction well explains the observed enhanced retention of H and He near the surface of W under both sequential and simultaneous bombardments. At ideal He/H ratio, He might suppress to a considerable extent the H blistering at the W surface. In a semiquantitative analysis, we decompose the strong He-H interaction into three parts, namely, an attractive force induced by valence electron depletion around He, repulsive forces contributed by elastic compression of the He-H separation and a H-H repelling in high-density electron gas.

• OSTI ID: 21366714
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 81, Issue 13; Other Information: DOI: 10.1103/PhysRevB.81.134112; (c) 2010 The American Physical Society; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
COMPRESSION
DENSITY FUNCTIONAL METHOD
ELECTRON DENSITY
ELECTRONS
HELIUM
HYDROGEN
INTERACTIONS
INTERSTITIALS
SIMULATION
SURFACES
THERMONUCLEAR REACTORS
TRAPPING
TRAPS
TUNGSTEN
VACANCIES
CALCULATION METHODS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
FLUIDS
GASES
LEPTONS
METALS
NONMETALS
POINT DEFECTS
RARE GASES
REFRACTORY METALS
TRANSITION ELEMENTS
VARIATIONAL METHODS