An energy-dispersive X-ray diffraction study of mean-square atom displacements in highly oriented pyrolytic graphite

The measurement of the mean-square thermal displacement 〈u²〉 of carbon atoms in highly oriented pyrolytic graphite (HOPG) in the hexagonal c direction is reported. Energy-dispersive X-ray diffraction (EDXD) has been used to study the integrated intensity of all Bragg reflections 004 through 0_′0_′14 as a function of temperature. It is demonstrated that the correction of the Bragg intensities due to thermal diffuse scattering contributions is very important for HOPG, when EDXD is used. The Debye temperature Θ_D = 554 (30) K is obtained.