Lattice dynamics of strontium oxide

The phonon dispersion relations of SrO at 300°K for the $\left[\zeta 00\right]$, $\left[\zeta \zeta 0\right]$, and $\left[\zeta \zeta \zeta \right]$ directions of propagation have been measured using inelastic neutron scattering. A shell model with seven parameters gives a good over-all description of the phonon dispersion relations. The phonon frequency distribution calculated with this model yields a temperature dependence of the characteristic Debye temperature which is in satisfactory agreement with results derived from specific-heat measurements. The second-order Raman spectrum of SrO is discussed on the basis of the neutron data and a calculated two-phonon density of states.