FINE STRUCTURE OF SPOTS IN ELECTRON DIFFRACTION RESULTING FROM PRESENCE OF PLANAR INTERFACES AND DISLOCATIONS .V. MULTIPLE BEAM CASE

A description is given of the fine structure of the electron beams transmitted and scattered by a plate‐shaped foil containing a stacking fault or an anti‐phase boundary inclined with respect to the surface. It is assumed that there are n strong diffracted beams. The transmitted and each strong scattered beam consists of n (n + 1) + 1 beams, very slightly different in orientation, and which give rise to the appearance of satellites of the diffraction spots. The geometry and the intensities of the satellite configurations are discussed. General properties can be derived from the formulation developed in the paper. Electrons leaving the crystal in a satellite beam direction are those which have changed from one wave field to another on crossing the fault boundary. The influence of the anomalous absorption, important for a thick crystal, is also examined. Satellite beams formed by electrons moving in a strongly absorbed wave field before or (and) after crossing the stacking fault, will be weak. A bright satellite is expected if one or both of these fields are easily transmitted. Finally it is shown that the intensities of the different satellite beams are not the same in different parts of the faulted region. Copyright © 1969 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim