Imperfections of crystal lattices as investigated by the study of X-ray diffuse scattering

A perfect crystal diffracts X rays only in discrete directions, given by the Bragg-Laue laws. All scattering observed in directions other than these, except Compton scattering, is due to imperfections of the crystal. The experimental method of obtaining useful scattering patterns and the principles of the calculation of actual structure from the distribution of anomalous scattering are described. Examples of application of this method to the study of thermal atomic movements, lattice deformations under mechanical stresses, defects of periodicity in diamond and in fibrous crystals, space-arrangement of atoms in solid solutions (order-disorder transformation, age-hardening) and scattering by small particles are briefly outlined.