Modeling of the lattice dynamics and elastic properties of the Sn2P2S6 ferroelectric

The lattice-dynamics calculations for the paraelectric phase of the Sn2P2S6 ferroelectric are performed within the model of rigid ions. The model para meters were chosen by fitting the calculated phonon spectra to the known da ta on inelastic neutron scattering. The dispersion curves obtained were the n used for calculating the orientational dependences of sound velocity and the variation of the phonon frequencies under the hydrostatic compression. The data obtained an in good agreement with the experimental results. (C) 2 000 MAIK "Nauka/Interperiodica".