A spectrophotometric investigation was made of the diffusion of Ti+ in pure, doped and pre-treated samples (table 72). The pure crystals were obtained from the melt, or were crystallized from aqueous solutions. The dopants were SrCl2 and BaCl2. It was found that the doping, and various other treatments, decreased the diffusivity; as compared with that in the molten sample. This was associated with a large increase in the apparent activation energy for diffusion. It was shown that the assumption of metastable supersaturated solutions of divalent impurity ions in the so-called pure material, led to a consistent and quantitative interpretation of the results.

Diffusion of Tl+ in Doped and Pretreated KCl. A.Glasner, R.Reisfeld, A.Linenberg: Physica Status Solidi B, 1967, 24[2], 695-706