The phonon-dispersion relations of graphite and the first-stage alkali-metal–graphite intercalation compounds have been calculated by a two-body carbon-carbon potential. In this proposed potential, in addition to the Born-Mayer constants A and ρ, two parameters for the stability of the graphite crystal along the a and c axes have been incorporated. Firstly, phonon dispersion in graphite has been investigated considering two neighbors within the plane and one neighbor between the planes. We have then extended this analysis to the evaluation of the phonon spectrum of first-stage potassium-graphite intercalation compound. Results obtained are in good agreement with the available experimental data.

• Received 13 December 1985

DOI:https://doi.org/10.1103/PhysRevB.33.7285