Asymmetric X-Ray Diffraction

Physical phenomena characteristic of asymmetric X-ray diffraction schemes for perfect crystals, including diffraction under conditions of specular reflection, have been considered in detail. The principles underlying asymmetric crystal monochromators, achievements in obtaining narrow collimated X-ray beams, and the latest results on the application of asymmetric schemes in the investigation of thin subsurface layers are stated; along with the fundamentals of asymptotic Bragg diffraction, specific features of the grazing Bragg-Laue scheme and the analysis of amorphous sublayers with the use of the surface Bragg peak. Emphasis is placed on the application of asymmetric diffraction schemes in the method of X-ray standing waves to increase sensitivity (in recording of photoelectrons, fluorescence, and Compton scattering) and to study the characteristic features of the diffraction process in strongly asymmetric geometry.