New interatomic potentials for studying the behavior of noble gas atoms in tungsten

• New potentials for W–He, W–Ne and W–Ar interactions were developed.
• The “s-band model” was used to describe the many-body interactions.
• The binding energies of an X atom to Xn or Xn–Vacancy clusters were obtained.
• The migration energies of X atoms and X clusters were discussed.

To study the behavior of noble gas atoms (He, Ne and Ar) in bulk tungsten, new DFT-based potentials for W–He, W–Ne and W–Ar interactions were developed by fitting the results obtained from density functional theory calculations. The new potentials adopt the embedded atom method (EAM) formalism, and the “s-band model” is used to describe the many-body interactions between each of the noble gas atoms and its neighboring W atoms. These potentials reproduce the formation energies of point defects and the migration barriers of single noble gas atoms. The simulations using these potentials successfully predict that the tetrahedral interstitial site is more stable than the octahedral interstitial site for X (= He, Ne or Ar) interstitials. Based on these new potentials, the binding interactions of a single X atom with the Xn and Xn–Vacancy clusters and the diffusion properties of Xn clusters in bulk W were studied using molecular dynamics (MD) simulations. The present results indicate that the binding energies obtained using the new potentials are good in agreement with the results of DFT calculations. The migration energies of the clusters increase with both the increase in the atomic radius of noble gases and the increase in the size of the clusters.