Self-trapping and diffusion of hydrogen in Nb and Ta from first principles

Per G. Sundell, Göran Wahnström

Resultado de la investigación: Article

37 Citas (Scopus)

Resumen

Interstitial hydrogen in bcc Nb and Ta is studied theoretically, using first-principles density-functional calculations. The effect of self-trapping is investigated in some detail, and our calculated energies, forces, and displacements for hydrogen at tetrahedral sites are all found to be in good agreement with experiments. The local motion of H and D is treated quantum mechanically by mapping out potential energy surfaces and solving a Schrödinger equation for the ground state and vibrationally excited states. Diffusion between sites is discussed in both the classical and the quantum regimes. At low temperatures, the small-polaron theory of phonon assisted tunneling is applied, and we find excellent agreement with experiments for both the calculated coincidence energy and bare tunneling matrix elements. At higher temperatures our results indicate that hydrogen migration should best be described in terms of overbarrier motion, rather than tunneling from excited states.

Idioma originalEnglish
PublicaciónPhysical Review B - Condensed Matter and Materials Physics
Volumen70
N.º22
DOI
EstadoPublished - 1 dic 2004

Huella dactilar

Hydrogen
trapping
Excited states
hydrogen
Gene Conversion
Potential energy surfaces
Chemical elements
Ground state
excitation
Density functional theory
interstitials
Experiments
potential energy
Temperature
ground state
energy
matrices

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Citar esto

@article{ddf18df6945b4a59a4cc6ab3aac81bb2,
title = "Self-trapping and diffusion of hydrogen in Nb and Ta from first principles",
abstract = "Interstitial hydrogen in bcc Nb and Ta is studied theoretically, using first-principles density-functional calculations. The effect of self-trapping is investigated in some detail, and our calculated energies, forces, and displacements for hydrogen at tetrahedral sites are all found to be in good agreement with experiments. The local motion of H and D is treated quantum mechanically by mapping out potential energy surfaces and solving a Schr{\"o}dinger equation for the ground state and vibrationally excited states. Diffusion between sites is discussed in both the classical and the quantum regimes. At low temperatures, the small-polaron theory of phonon assisted tunneling is applied, and we find excellent agreement with experiments for both the calculated coincidence energy and bare tunneling matrix elements. At higher temperatures our results indicate that hydrogen migration should best be described in terms of overbarrier motion, rather than tunneling from excited states.",
author = "Sundell, {Per G.} and G{\"o}ran Wahnstr{\"o}m",
year = "2004",
month = "12",
day = "1",
doi = "10.1103/PhysRevB.70.224301",
language = "English",
volume = "70",
journal = "Physical Review B - Condensed Matter and Materials Physics",
issn = "1098-0121",
publisher = "American Physical Society",
number = "22",

}

Self-trapping and diffusion of hydrogen in Nb and Ta from first principles. / Sundell, Per G.; Wahnström, Göran.

En: Physical Review B - Condensed Matter and Materials Physics, Vol. 70, N.º 22, 01.12.2004.

Resultado de la investigación: Article

TY - JOUR

T1 - Self-trapping and diffusion of hydrogen in Nb and Ta from first principles

AU - Sundell, Per G.

AU - Wahnström, Göran

PY - 2004/12/1

Y1 - 2004/12/1

N2 - Interstitial hydrogen in bcc Nb and Ta is studied theoretically, using first-principles density-functional calculations. The effect of self-trapping is investigated in some detail, and our calculated energies, forces, and displacements for hydrogen at tetrahedral sites are all found to be in good agreement with experiments. The local motion of H and D is treated quantum mechanically by mapping out potential energy surfaces and solving a Schrödinger equation for the ground state and vibrationally excited states. Diffusion between sites is discussed in both the classical and the quantum regimes. At low temperatures, the small-polaron theory of phonon assisted tunneling is applied, and we find excellent agreement with experiments for both the calculated coincidence energy and bare tunneling matrix elements. At higher temperatures our results indicate that hydrogen migration should best be described in terms of overbarrier motion, rather than tunneling from excited states.

AB - Interstitial hydrogen in bcc Nb and Ta is studied theoretically, using first-principles density-functional calculations. The effect of self-trapping is investigated in some detail, and our calculated energies, forces, and displacements for hydrogen at tetrahedral sites are all found to be in good agreement with experiments. The local motion of H and D is treated quantum mechanically by mapping out potential energy surfaces and solving a Schrödinger equation for the ground state and vibrationally excited states. Diffusion between sites is discussed in both the classical and the quantum regimes. At low temperatures, the small-polaron theory of phonon assisted tunneling is applied, and we find excellent agreement with experiments for both the calculated coincidence energy and bare tunneling matrix elements. At higher temperatures our results indicate that hydrogen migration should best be described in terms of overbarrier motion, rather than tunneling from excited states.

UR - http://www.scopus.com/inward/record.url?scp=13844275329&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.70.224301

DO - 10.1103/PhysRevB.70.224301

M3 - Article

VL - 70

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

SN - 1098-0121

IS - 22

ER -