Raman microprobe observation of intercalate contraction in graphite intercalation compounds

Abstract

Raman microprobe spectra of ${\mathrm{SbCl}}_{5}$, ${\mathrm{Br}}_{2}$, and ${\mathrm{FeCl}}_{3}$ graphite intercalation compounds have been obtained with a spatial resolution of 2 \ensuremath{\mu}m. Depletion of the intercalate was observed within 10 \ensuremath{\mu}m of the sample edge in the ${\mathrm{SbCl}}_{5}$-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 ${\mathrm{Br}}_{2}$ and ${\mathrm{FeCl}}_{3}$ graphite intercalation compounds, consistent with the low intercalation temperature of the former and the small thermal expansion coefficient of the latter.