The phonon dispersion relation for magnesium oxide

Abstract

Inelastic neutron scattering from magnesium oxide at room temperature has been measured and the frequencies of 656 phonons with wave vectors in mirror planes deduced. The results are shown to be in good agreement with dispersion relations calculated on the basis of a shell model, the parameters of which were obtained from independent measurements of the elastic constants, dielectric constants and infra-red dispersion frequency.