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Crystal dynamics of caesium fluoride

1973; IOP Publishing; Volume: 6; Issue: 20 Linguagem: Inglês

10.1088/0022-3719/6/20/006

1747-3802

W. Bührer,

Nuclear Physics and Applications

The dispersion relation for the normal modes of vibration in CsF at 295 K has been determined from neutron coherent inelastic scattering data obtained on the triple axis crystal spectrometer at the Saphir reactor, Wurenlingen. With an improved resolution of the spectrometer, the slopes of the acoustic branches near q=0 have been investigated at 85 K and 295 K to determine the velocities of sound and the elastic constants. The phonon frequencies are well fitted by a seven-parameter shell model involving nearest-neighbour interactions, a varying ionic charge, and the polarizabilities of both ions. The model was used to compute various physical properties of CsF to compare with other experiments.