Molecular dynamics simulation of low-energy atomic hydrogen on tungsten surface

The trapping and release of hydrogenic particles is a crucial issue in the application of tungsten (W) as plasma-facing materials (PFM) in current fusion devices. To study the interaction of low-energy atomic hydrogen with W surface, molecular dynamics (MD) simulations were performed adopting a bond-order interatomic potential. Energetic hydrogen atoms with a series of energies ranged from 0.5 eV to 50 eV were projected on the W (0 0 1) surface at normal incidence. The particle and energy reflection coefficients as well as mean range distribution as a function of incident energy have been discussed. Also calculated were the interstitial hydrogen formation energies and the migration energy. For an interstitial hydrogen atom in W, the most favorable configuration is in the tetrahedral position and the migration energy is obtained as about 0.30 eV, in agreement with experimental data.