LATTICE-DYNAMICS OF PYRITE FES2 BY COHERENT NEUTRON-SCATTERING

The phonon dispersion of FeS2 has been investigated by coherent inelastic neutron scattering. The experimental data, i.e. frequencies and intensities as function of the wave vector, were analysed with a rigid ion model with short-range valence forces. The model gives a good description of the vibrational frequencies as well as of the atomic displacements. Derived properties like dielectric constant, specific heat, and Debye-Waller factors compare well with corresponding experiments.