Neutron scattering by anharmonic crystals and the effect of sublattice displacements

A theory has been described for the scattering of neutrons by anharmonic crystals, for which terms of the type Vsup(3) (k1j1;-k1j1;aj) which contribute to the sublattice displacements are not neglected. It is shown that the sublattice displacements will modify the phase factor arising from the scattering by any atom in the unit cell, and the Debye-Waller factor also gets altered both by the sublattice displacements as well as by higher order terms arising from anharmonicity. (author)