Raman microprobe observation of intercalate contraction in graphite intercalation compounds

Raman microprobe spectra of SbCl5, Br2, and FeCl3 graphite intercalation compounds have been obtained with a spatial resolution of 2 m. Depletion of the intercalate was observed within 10 m of the sample edge in the SbCl5-graphite samples, and this observation is found to be consistent with a model in which the intercalate contracts thermally as the sample is cooled after the intercalation reaction is completed. No depletion was observed in the Br2 and FeCl3 graphite intercalation compounds, consistent with the low intercalation temperature of the former and the small thermal expansion coefficient of the latter.