Electron momentum distribution in graphite and lithium-intercalated graphite

Compton profiles of the first-stage graphite intercalation compound Li${\mathrm{C}}_6$ have been calculated using the self-consistent pseudopotential method within the local-density-functional formalism. The difference between profiles of Li${\mathrm{C}}_6$ and graphite exhibits characteristic features which provide further elucidation of the electronic properties of intercalation. It is found that the change in the electron momentum distribution in Li${\mathrm{C}}_6$ is qualitatively different from that predicted by the generally accepted rigid-band model.