On the Temperature Diffuse Scattering of Electrons I. Derivation of General Formulae

The perturbation theory of the temperature diffuse scattering of electrons is presented taking account of the fact that each of the primary and secondary waves in the crystal consists of many plane waves. Formulae for the intensity of the diffuse scattering from a monatomic crystal forming a primitive lattice are obtained for each of the perturbation potentials due to Bloch and to Nordheim. When each of the primary and secondary waves does not excite any Bragg reflexions and can be given by a plane wave, the Nordheim potential gives the same result and the Bloch potential gives practically the same result as that of the current X-ray diffraction theory applied to electron diffraction. The result may be applied to explain the formation of the Kikuchi pattern by the temperature diffuse scattering and the anomalous intensity variation of the diffuse spot from some single crystals.