The serial sectioning technique was used to study the diffusion of 22Na in single crystals at 368 to 593C. The results could be described by:

D (cm2/s) = 78.5 exp[-35.05(kcal/mol)/RT]

Na-22 Diffusion in CsI Single Crystals. S.M.Klotsman, I.P.Polikarpova, A.N.Timofeev: Fizika Tverdogo Tela, 1969, 11[9], 2710-2