Diffuse neutron scattering from β- and α-AgI

The diffuse scattering from the β-and α-phases of silver iodide powder has been examined by neutrons of wavelength λ = 1.07 Å. In the case of the β-phase, the experimental results are explained by thermal diffuse scattering. In the α-phase, an intense contribution to the diffuse scattering is also due to the structural disorder of the silver ions. Possibly the cation disorder causes considerable quasistatic displacements of the iodide ions giving rise to supplementary diffuse scattering.