The isotope effect for the diffusion of hydrogen in niobium

Abstract
The isotope effect for the diffusion of hydrogen, deuterium and tritium in BCC niobium has been measured using the Gorsky effect. In the temperature range 190-310K the data can be represented by Arrhenius relations. The ratio DH/DD is much larger than the classical value of square root 2 and shows a strong temperature dependence. The ratio DD/Dt is slightly larger than square root 3/2 and is relatively temperature-independent. These results are not explicable on the basis of current theory.