Dynamical theory of diffraction of plane and spherical waves by a periodic system of scatterers with isolated defects

Using the T-matrix formalism a method known from the crystal lattice dynamics is applied to the study of the diffraction of radiation by a crystal with isolated defects. The following cases are discussed: substitutional foreign atoms or vacancies without lattice deformation, lattice deformation, interstitial atoms. Plane or spherical primary incident scalar waves are considered.