Dissolution, diffusion and permeation behavior of hydrogen in vanadium: A first-principles investigation

Employing a first-principles method, we have studied the stability, diffusivity, and permeation properties of hydrogen (H) and its isotopes in bcc vanadium (V). A single H atom is found to favor the tetrahedral interstitial site (TIS) in V. The charge density distribution exhibits a strong interaction between H and its neighbor V atoms. Analysis of DOS and Bader charge reveals that the occupation number of H-induced low energy states is directly associated with the stability of H in V. Further, H is shown to diffuse between the neighboring TISs with a diffusion barrier of 0.07eV. Diffusion coefficients and permeabilities of H isotopes in V are estimated with empirical theory. At a typical temperature of 800K, the diffusion coefficient and the permeability of H are 2.48 × 10^-4cm²s^-1 and 2.19 × 10^-9molm^-1s^-1Pa^-/2, respectively.