Skip to Main content Skip to Navigation
Journal articles

Surface coverage dependent mechanisms for the absorption and desorption of hydrogen from the W(110) and W(100) surfaces: a DFT investigation

Abstract : Herein we investigate absorption and desorption of hydrogen in the sub-surface of tungsten via Density Functional Theory. Both the near-surface diffusion and recombination of a bulk hydrogen atom with a hydrogen atom adsorbed upon the W(110) and W(100) surfaces are investigated at various surface adsorption coverage ratios. This study intends to model the desorption processes occurring during Thermal-Desorption Spectroscopy experiments and the absorption of hydrogen during gaseous or low energy atomic exposure. Since the diffusion and recombination processes are expected to change as the hydrogen coverage of the surface varies, different coverage ratios were investigated on both surfaces. We found that at saturation coverage of hydrogen on both surfaces, the activation barriers for the recombination of molecular hydrogen are below 0.8 eV. On the contrary, below saturation, the activation barriers for recombination rise to 1.35 eV and 1.51 eV depending on the coverage and on the orientation of the surface. Regarding the absorption of atomic hydrogen from the surface into the bulk, the activation barrier raises from less than 1.0 eV at saturation to around 1.7 eV below saturation on both surfaces. These results indicate that surface mechanisms certainly play a significant role in the kinetics of desorption of hydrogen from tungsten; it is also expected that surface mechanisms affect the total amount on hydrogen absorbed in tungsten during implantation.
Document type :
Journal articles
Complete list of metadatas

Cited literature [68 references]  Display  Hide  Download

https://hal-amu.archives-ouvertes.fr/hal-02879798
Contributor : Régis Bisson <>
Submitted on : Wednesday, June 24, 2020 - 11:43:00 AM
Last modification on : Thursday, June 25, 2020 - 3:35:58 AM

File

R2_Wsurf_Hcov-1.pdf
Files produced by the author(s)

Licence


Distributed under a Creative Commons Attribution - NonCommercial - NoDerivatives 4.0 International License

Identifiers

  • HAL Id : hal-02879798, version 1

Collections

Citation

M Ajmalghan, Z Piazza, E. Hodille, Y. Ferro. Surface coverage dependent mechanisms for the absorption and desorption of hydrogen from the W(110) and W(100) surfaces: a DFT investigation. Nuclear Fusion, IOP Publishing, 2019, 59 (10), pp.106022. ⟨hal-02879798⟩

Share

Metrics

Record views

47

Files downloads

52

Données de recherche