Trapping of multiple hydrogen atoms in a tungsten monovacancy from first principles

Abstract

The configuration of multiple hydrogen atoms trapped in a tungsten monovacancy is investigated using first-principles calculations. Unlike previous computational studies, which have reported that hydrogen in bcc metal monovacancies occupies octahedral interstitial sites, it is found that the stable sites shift toward tetrahedral interstitial sites as the number of hydrogen atoms increases. As a result, a maximum of twelve hydrogen atoms can become trapped in a tungsten monovacancy.

Dynamic fuel retention in tokamak wall materials: An in situ laboratory study of deuterium release from polycrystalline tungsten at room temperature

“…This is an extended experimental program in itself and it is not the subject of the present study. However our results can be discussed in view of the recent theoretical investigations at the ab initio level for the interaction of deuterium with natural bulk defects in tungsten such as single vacancy [22][23][24][25][26][27], grain boundary [28,29], and dislocation [29]. All these defects can accommodate several deuterium atoms in their vicinity.…”

Object kinetic Monte Carlo simulations of irradiated tungsten for nuclear fusion reactors

“…Binding energies for H atoms to V m and H n V m clusters are summarized in Table 3.8. In the case of H trapped in a single vacancy (H n V), the results [128] are in good agreement with previously published data [122,[130][131][132][133] as observed in Figure 3.4. [128]) are compared to those obtained by Johnson et al [131], Heinola et al [132], Ohsawa et al [133], Liu et al [130] and Fernandez et al [122].…”

“…Johnson et al [131], Heinola et al [132], Ohsawa et al [133], Liu et al [130] and Fernandez et al [122] The region between 0 and 150 nm (in blue) has been taken into account neither in the results nor in the discussion because it is highly influenced by surface contamination [49] is divided into small boxes, called "mesh elements". The "mesh element"…”

“…[122,123,128,[130][131][132][133], show a binding energy of a H atom to a vacancy higher than 1 eV (see Figure 3.5). Nanostructured materials have a large density of grain boundaries (GBs) which, depending on the irradiation conditions, have a clear influence on the distribution of both FPs and light species such as H [49].…”

Dissolving, trapping and detrapping mechanisms of hydrogen in bcc and fcc transition metals

“…9,17 According to previous first-principles calculations, a maximum of 6 H atoms could be held in a vacancy in many metals including Fe, [17][18][19] Cr, 19 Nb, 19 V, 19 Ta 19 and Pd. 20 While 11 H and 12 H atoms could be accommodated in a vacancy in Mo 19 and W, 19,[21][22][23] respectively. The disparity in the maximum number of H atoms accommodated in a vacancy is found in Al, 2,24 which is attributed to different definitions of the trapping energy of H in a vacancy.…”