The dispersion curves along the directions [100] and [001] of have been measured by inelastic neutron scattering. The results are analysed with different rigid-ion models: Born - von Karman and valence force field models, which give a good agreement with experiments. Additional measurements of the acoustical branches allow us to determine elastic stiffness constants which are () , , , , , . The compressibility calculated from these constants is in accordance with the experimental value.

The phonon dispersion curves along the [100] and [001] directions of CuInSe2 have been measured by inelastic neutron scattering. The neutron measurements reveal the uncertainty of optical measurements because of the large absorption of this material. The lattice dynamics is analysed with a rigid ion model: Born-von Karman short range interactions associated with long range electrostatic forces. The calculated dispersion curves are in good agreement with the experiment. The atomic displacements associated with each vibrational mode are used to discuss the optical phonons. The obtained results provide a strong experimental basis from which we can validate the ab initio methods.

No abstract