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

Muthali Ajmalghan, Zachary Piazza, Etienne Hodille, Yves Ferro

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

Kuvaus

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.
Alkuperäiskielienglanti
Artikkeli106022
LehtiNuclear Fusion
Vuosikerta59
Numero10
Sivumäärä12
ISSN0029-5515
DOI - pysyväislinkit
TilaJulkaistu - lokakuuta 2019
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä, vertaisarvioitu

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Ajmalghan, Muthali ; Piazza, Zachary ; Hodille, Etienne ; Ferro, Yves. / Surface coverage dependent mechanisms for the absorption and desorption of hydrogen from the W(110) and W(100) surfaces : a density functional theory investigation. Julkaisussa: Nuclear Fusion. 2019 ; Vuosikerta 59, Nro 10.
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title = "Surface coverage dependent mechanisms for the absorption and desorption of hydrogen from the W(110) and W(100) surfaces: a density functional theory 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.",
keywords = "ATOMIC-HYDROGEN, DEUTERIUM RETENTION, DFT, DIFFUSION, FUEL RETENTION, IN-SITU, MOLECULAR-DYNAMICS, NUCLEAR-REACTION, TEMPERATURE, TUNGSTEN, VACANCY, activation barriers, coverage, desorption, hydrogen, surface, tungsten, 114 Physical sciences",
author = "Muthali Ajmalghan and Zachary Piazza and Etienne Hodille and Yves Ferro",
year = "2019",
month = "10",
doi = "10.1088/1741-4326/ab33e7",
language = "English",
volume = "59",
journal = "Nuclear Fusion",
issn = "0029-5515",
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number = "10",

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Surface coverage dependent mechanisms for the absorption and desorption of hydrogen from the W(110) and W(100) surfaces : a density functional theory investigation. / Ajmalghan, Muthali; Piazza, Zachary; Hodille, Etienne; Ferro, Yves.

julkaisussa: Nuclear Fusion, Vuosikerta 59, Nro 10, 106022, 10.2019.

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

TY - JOUR

T1 - Surface coverage dependent mechanisms for the absorption and desorption of hydrogen from the W(110) and W(100) surfaces

T2 - a density functional theory investigation

AU - Ajmalghan, Muthali

AU - Piazza, Zachary

AU - Hodille, Etienne

AU - Ferro, Yves

PY - 2019/10

Y1 - 2019/10

N2 - 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.

AB - 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.

KW - ATOMIC-HYDROGEN

KW - DEUTERIUM RETENTION

KW - DFT

KW - DIFFUSION

KW - FUEL RETENTION

KW - IN-SITU

KW - MOLECULAR-DYNAMICS

KW - NUCLEAR-REACTION

KW - TEMPERATURE

KW - TUNGSTEN

KW - VACANCY

KW - activation barriers

KW - coverage

KW - desorption

KW - hydrogen

KW - surface

KW - tungsten

KW - 114 Physical sciences

U2 - 10.1088/1741-4326/ab33e7

DO - 10.1088/1741-4326/ab33e7

M3 - Article

VL - 59

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

IS - 10

M1 - 106022

ER -