Structural analysis according to reduced data: VIII. Refinement of the extended model of aspherical atoms

A program for the refinement of the model of aspherical atoms within the Stewart-Hansen-Coppens formalism has been developed. Deformation scattering up to the 8th expansion order in multipoles has been taken into account for the first time. The program was tested for 11 crystals. The effect of the result of interpolation of radial scattering curves on the model parameters is considered. The importance of introduction of multipoles of high (5th–8th) orders into the model for a number of crystals is shown. The use of the extended multipole model for a silicon crystal revealed some new specific features of the electronic structure: consideration of multipoles up to the 7th order makes it possible to explain the intensity of the forbidden 222 reflection.