Crystal dynamics of magnesium oxide

Phonon dispersion curves, for MgO, have been calculated, for the first time, in the framework of the modified three body force shell model (TSM), assuming both the positive and negative ions to be polarizable. The results are in good agreement with the inelastic neutron scattering measurements and are somewhat better than our earlier one-ion polarizable TSM calculations. It has been possible to conclude that a revised set of values of the elastic constants which are relatively larger, is essentially responsible to lead to a better set of model parameters and hence of the phonon frequencies.