The pi-electronic excitations in graphite layers are studied within th
e self-consistent-field approach. The pi plasmon behaves as an optical
plasmon, mainly due to the pi-band characteristics. The excitation sp
ectra and the pi-plasmon frequencies are obviously enhanced by the int
erlayer Coulomb interactions and increase with the number of graphite
layers. (C) 1997 Published by Elsevier Science Ltd.