Relaxation Process Due to Long-Range Diffusion of Hydrogen and Deuterium in Niobium

Abstract

We have applied a new method for the determination of diffusion coefficients to hydrogen and deuterium in niobium. The activation energies for both isotopes are comparatively small and differ by about 20%, whereas ${D}_{0}$ is the same within experimental error. The activation energy for hydrogen diffusion is equal to the energy difference $\ensuremath{\hbar}{\ensuremath{\omega}}_{\mathrm{H}}=114\ifmmode\pm\else\textpm\fi{}6$ meV between the ground state and the first excited state of the hydrogen atom in solution.