It was found that the data for 35S, at 600 to 900C, could be described by:

D (cm2/s) = 1.65 x 100 exp[-40.0(kcal/g-atom)/RT]

N.Barbouth, J.Oudar, J.Cabane: Comptes Rendus de l’Academie des Sciences, 1967, 264, 1029-31