Phonon Spectrum of Graphite

Abstract

The phonon spectrum of reactor grade graphite is computed by means of the essentially exact root sampling technique for a sampling 47 788 points in an irreducible segment of the Brillouin zone. Measurements of the specific heat (over the range 100°—1000°K) are used to determine the force constants, resulting in good agreement of the calculated phonon spectrum, and neutron scattering measurements.