1. Specificity of fast electron diffraction

Matter can be explored on an atomic scale, thanks to the interaction between atoms and incident radiation of wavelengths comparable to or shorter than the interatomic distances. This results in scattering of the incident beam, which is prepared in the form of a plane wave [exp i k r ], with its direction of propagation modified as it passes through the specimen. For an incident monochromatic plane wave and a topologically ordered crystal, only discrete directions of propagation are active after interaction; this is the diffraction phenomenon [M 4 126]...