An investigation was made of the self-diffusion of 131I in monocrystalline and polycrystalline material; using both the sectioning and Gruzin methods. The data (tables 195 and 196) indicated that intercrystalline diffusion within the temperature range studied did not contribute significantly to the diffusion process. The combined results for single crystals, at 405 to 560C, could be described by:

D (cm2/s) = 0.39 exp[-29.15(kcal/mol)/RT]

while those at 155 to 280C could be described by:

D (cm2/s) = 2.6 x 10-5 exp[-16.5(kcal/mol)/RT]

The combined results for polycrystals at 405 to 560C could be described by:

D (cm2/s) = 0.85 exp[-30.20(kcal/mol)/RT]

while those at 155 to 338.5C could be described by:

D (cm2/s) = 2 x 10-5 exp[-16.15(kcal/mol)/RT]

The polycrystals which were used were prepared via the deformation and recrystallization of monocrystals.

Cesium-134 and Iodine-131 Self-Diffusion in Cesium Iodide Single and Polycrystals. S.M.Klotsman, I.P.Polikarpova, A.N.Timofeev, I.S.Trakhtenberg: Fizika Tverdogo Tela, 1967, 9[9], 2487-502

Table 194

Self-Diffusion of 134Cs in Polycrystalline CsI