A study was made of the self-diffusion of 18F in single crystals by using serial sectioning and radioactivity counting of the remaining specimen. It was found that the data, for temperatures ranging from 350 to 940C, could be described by:

D (cm2/s) = 3.1 exp[-1.6(eV)/kT]

The F defects, both vacancies and interstitials, were much more mobile than were the cation defects.

Fluorine Self-Diffusion in CaF2 and BaF2. H.J.Matzke: Journal of Materials Science, 1970, 5[10], 831-6

Figure 30

Diffusion of F in BaF2