An in situ ESR study of specially cut highly oriented pyrolytic graphite indicates dramatic changes in the ESR line shape (A/B ratio) and intensity upon exposure to a fluorine atmosphere. The results could be interpreted by the formation of a macroscopic intercalation layer and the advance of a boundary separating the intercalated and non-intercalated highly oriented pyrolytic graphite. Using a theoretical model previously developed for the ESR of layer-substrate systems, the thickness of the intercalated layer was extracted as a function of the exposure time and the diffusion coefficient of fluorine into the highly oriented pyrolytic graphite.

Diffusion and Intercalation of Fluorine into Highly Oriented Pyrolytic Graphite: an in Situ ESR Study. Palchan, I., Davidov, D., Zevin, V., Polatsek, G., Selig, H.: Physical Review B, 1985, 32[8], 5554-7

Figure 11

Diffusion of K in graphite (C24K)