Dynamical treatment of Kikuchi patterns

A dynamical theory of Kikuchi patterns from thick crystals is developed, which takes into account the absorption of both the elastically and inelastically scattered electrons. The wave function describing the state of an inelastically scattered electron due to an elementary excitation of core electrons of the crystal atoms is calculated. The general formulae for the intensity of the pair of Kikuchi lines (hkl) and () and bands are obtained. The intensity profiles of Kikuchi lines and bands are analyzed. For a thick crystal the `defect' line contrast and band contrast are reversed as a result of anomalous absorption of the inelastically scattered electrons. This is in accordance with observed experimental data.