Saturation of tungsten surfaces with hydrogen: A density functional theory study complemented by low energy ion scattering and direct recoil spectroscopy data
| Autor: | Robert Kolasinski, Zachary A. Piazza, M. Ajmalghan, Yves Ferro |
|---|---|
| Přispěvatelé: | Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2018 |
| Předmět: |
low energy ion spectroscopy
Materials science Polymers and Plastics Hydrogen tungsten chemistry.chemical_element 02 engineering and technology Tungsten DFT 01 natural sciences Molecular physics 0103 physical sciences Monolayer surface Physics::Atomic Physics 010306 general physics Spectroscopy Metals and Alloys Hydrogen atom 021001 nanoscience & nanotechnology Electronic Optical and Magnetic Materials [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry chemistry Low-energy ion scattering hydrogen [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] Ceramics and Composites Density functional theory 0210 nano-technology Saturation (chemistry) |
| Zdroj: | Acta Materialia Acta Materialia, 2018, 145, pp.388-398. ⟨10.1016/j.actamat.2017.12.029⟩ Acta Materialia, Elsevier, 2018, 145, pp.388-398. ⟨10.1016/j.actamat.2017.12.029⟩ |
| ISSN: | 1359-6454 |
| Popis: | International audience; Herein, we investigate the saturation limits of hydrogen on the (110) and (100) surfaces of tungsten via Density Functional Theory (DFT) and complement our findings with experimental measurements. We present a detailed study of the various stable configurations that hydrogen can adopt upon the surfaces at coverage ratios starting below 1.0, up to the point of their experimental coverage ratios, and beyond. Our findings allow us to estimate that the saturation limit on each surface exists with one monolayer of hydrogen atoms adsorbed. In the case of (110) this corresponds to a coverage ratio of one hydrogen atom per tungsten atom, while in the case of (100) a full monolayer is present at a coverage ratio of 2.0. Preliminary Low Energy Ion Scattering (LEIS) and Direct Recoil Spectroscopy (DRS) measurements complement these results and tend to confirm the findings obtained by DFT. In particular, the preferred adsorption sites on both surfaces at any coverage, the reconstruction of the (100) surface and the saturation limits agree well. We show that depending on the coverage, hydrogen surface binding energies can be of the same magnitude as binding energies to defects like vacancies. As a consequence, surface effects should be included in models aiming to simulate retention and desorption of hydrogen from the bulk. |
| Databáze: | OpenAIRE |
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