Ab initio modeling of quasielastic neutron scattering of hydrogen pipe diffusion in palladium

Emily J. Schiavone, Dallas Trinkle

Research output: Contribution to journalArticle

Abstract

A recent quasielastic neutron scattering (QENS) study of hydrogen in heavily deformed fcc palladium provided the first direct measurement of hydrogen pipe diffusion, which has a significantly higher diffusivity and lower activation barrier than in bulk. While ab initio estimates of hydrogen diffusion near a dislocation corroborated the experimental values, open questions remain from the Chudley-Elliott analysis of the QENS spectra, including significant nonmonotonic changes in jump distance with temperature. We calculate the spherically averaged incoherent scattering function at different temperatures using our ab initio data for the network of site energies, jump rates, and jump vectors to directly compare to experiment. Diffusivities and jump distances are sensitive to how a single Lorentzian is fit to the scattering function. Using a logarithmic least squares fit over the range of experimentally measured energies, our diffusivities and jump distances agree well with those measured by experiment. However, these calculated quantities do not reflect barriers or distances in our dislocation geometry. This computational approach allows for validation against experiment, along with a more detailed understanding of the QENS results.

Original languageEnglish (US)
Article number054114
JournalPhysical Review B
Volume94
Issue number5
DOIs
StatePublished - Aug 26 2016

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Palladium
Neutron scattering
palladium
Hydrogen
neutron scattering
Pipe
diffusivity
scattering functions
hydrogen
incoherent scattering
Incoherent scattering
Experiments
activation
Chemical activation
temperature
energy
Scattering
estimates
geometry
Temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Ab initio modeling of quasielastic neutron scattering of hydrogen pipe diffusion in palladium. / Schiavone, Emily J.; Trinkle, Dallas.

In: Physical Review B, Vol. 94, No. 5, 054114, 26.08.2016.

Research output: Contribution to journalArticle

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