A technique was used in which H2O was diffused into the halide. Formation of H2 then occurred within the crystal, and the H2 diffusion coefficient could be deduced from measurements of the growth kinetics of KH and KOH layers. The results for temperatures ranging from 180 to 400C could be described by:

D (cm2/s) = 50 exp[-0.81(eV)/kT]

New Method for the Determination of the Diffusion Coefficient of H in Alkali Halides. H.Gruendig, C.Rühenbeck: Zeitschrift für Physik, 1972, 249[3], 269-78