Effect of interatomic potential on the energetics of hydrogen and helium-vacancy complexes in bulk, or near surfaces of tungsten.
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| Title: | Effect of interatomic potential on the energetics of hydrogen and helium-vacancy complexes in bulk, or near surfaces of tungsten. |
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| Authors: | Yang, L.1 liyang@utk.edu, Bergstrom, Z.J.1, Wirth, B.D.1,2 bdwirth@utk.edu |
| Source: | Journal of Nuclear Materials. Dec2018, Vol. 512, p357-370. 14p. |
| Subjects: | Interatomic angles, Helium, Hydrogen bonding, Binding energy, Molecular structure |
| Abstract: | Abstract Hydrogen (H) trapping by helium-vacancy (He V) complexes in bulk and the near surface region of tungsten (W) have been investigated by molecular statics calculations that evaluate two different W H interatomic potentials, which use the same W He, He He and He H potentials. One of the W H potentials is a bond-order potential (BOP) developed by Juslin et al. , while the other is an embedding atom method (EAM) potential developed by Wang et al.. Both potentials overestimate the H binding energies to He clusters in bulk W, as compared to DFT calculations, but properly predict the functional form of the H binding energies to He clusters with increasing number of He and H. The BOP simulations reveal that H binding energies to He x V complexes generally increase with increasing number of He. However, the EAM results indicate that the H binding energy as a function of number of He depends on the number of H, and the H binding energies change slightly at high He content. Compared with available DFT data, both BOP and EAM underestimate the H binding energies to He x V 2 H m complexes. The BOP reproduces the He formation energy below a W surface, while the EAM potential better reproduces the H formation energy and the interactions between H and He V complexes. Based on these comparisons, we determine that the EAM potential is more accurate than BOP for large-scale molecular dynamics simulations of W He H interactions. The EAM potential predicts that the difference in the average binding energies of H to stable He V complexes near the W surface is less than 0.2 eV and the difference decreases with increasing He content. Thus, the EAM potential indicates that the effect of surfaces on H binding energies to large He V complexes below the W surfaces can be ignored. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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