Anisotropy of the Scattering of X Rays and Electrons by Cubic Crystals

An analysis is given of the influence of perturbing fields of the Oh and Td symmetry on the x-ray and the electron scattering form factors. The results obtained are used to calculate the structure amplitudes for bcc and fcc lattices. It is shown that the anisotropy of the x-ray or the electron scattering in transition metals should be observed in single-crystal and polycrystalline samples. The changes in the relative intensities in the x-ray diffraction patterns resulting from deviations of the spatial electron distribution from the central symmetry may reach 20–40% for elements in the second period and 4–5% for transition metals. The corresponding changes in the electron diffraction patterns should be somewhat smaller. Thus, for transition metals, the changes in the electron diffractograms should be about 1%.