The diffusivities were determined at 20 to 100C. It was found that the results depended upon the D concentration and could be described by:

high concentrations:     D (cm2/s) = 3.45 x 10-3 exp[-5.3(kcal/g-atom)/RT]

low concentrations:     D (cm2/s) = 2.5 x 10-3 exp[-5.15(kcal/g-atom)/RT]

G.Bohmholdt, E.Wicke: Zeitschrift für Physikalische Chemie, 1967, 56, 133-54