BULK AND SURFACE DYNAMICS OF GRAPHITE WITH THE BOND CHARGE MODEL

The bond charge model (BCM), originally designed by Weber for the dynamics of tetrahedrally coordinated semiconductors, is shown to be applicable, with minor adjustments, to sp2 configurations. Calculations for the bulk and surface dynamics of graphite, based on a comparatively small number of adjustable parameters (five or six), are shown to be in excellent agreement with recent inelastic helium atom scattering data and high-resolution electron-energy-loss spectroscopy. The parameter transferability to other forms of sp2-bonded carbons is discussed with the indication that BCM is easily applicable to large structures (e.g., giant fullerenes) presently inaccessible to ab initio methods, with a comparatively modest computational effort.