Quantum‐mechanical calculations for hydrogen in niobium and tantalum. II. Diffusion coefficients

Abstract

Abstract Results of quantitative theoretical investigations are presented concerning the diffusion coefficients of H and D in Nban Ta. They are based on the quantum theory of the diffusion of light interstitials and take into account the lattice‐configuration dependence of the hydrogen tunneling integrals and the effects of adiabatic saturation of the transition rate. Thecalculations make use of a semiempirical hydrogen‐host‐lattice interaction potential which is adapted to experimental data from outside the diffusion phenomena. The resulting theoretical values for the diffusion coefficients agree well with the experimental observations.