PHONON-DISPERSION IN GRAPHITE USING A 2-BODY POTENTIAL APPROACH

A two-body potential has been proposed for graphite. In addition to the Born-Mayer constants A and rho , the proposed potential contains two parameters for the stability of the crystal along a and c axis. The potential parameters were determined with the help of experimental elastic constants. Using this potential, the phonon dispersion in graphite is calculated in (ooq) and (qoo) directions. The interactions were considered up to two neighbours in the plane and one neighbour between the planes. The theoretical results agree with the available experimental ones, especially the agreement for the A//2//u out of plane mode at 686 cm** minus **1.