A historical and physical review of the Kikuchi pattern is performed. In §2, a geometrical optics of the Kikuchi pattern is given, and we show that it is difficult to interpret the Kikuchi band by such a method. A simplified physical optics on Kikuchiband formation is given in §3, where the coherency of the inelastically-scattered electrons in the crystal is discussed in detail. In §4 and §5, we give a dynamical theory of the Kikuchi pattern considering the single-electron excitations and phonon excitations. As a recent topical theories of H. K lines and LEED-Kikuchi patten are presented in detail.
This article is a review of the short notes by the author published in Acta Cryst., A29, 724 (1973) and ibid., A30, 600 (1974) . The method for the accurate determination of low order structure factors from the thickness fringes in electron micrographs are described in more detail. Applications to magnesium oxide, silicon and cadmium sulfide are given. For cadmium sulfide, which is a non-centrosymmetric crystal, the phase angle of the crystal structure factor was determined as well as the absolute value.
The idea and some remarks on the developement of the“Complete Automatic Analyzer of Molecular Structure”are described. It means a combined hardware and software system which, starting with a tiny crystal specimen mounted on a goniometer-head of a dif f ractometer, automatically runs through up to the final structure display without any intermediate input procedures based on crystallographer's decision. In other words, this system may be translated as a“Microscope”to see molecular structure in a resolution of less than one Ångstrom unit. The limit and scope of the system is considered, and some preliminary results including the computer program of automatic crystal structure analysis by the use of the Patterson function are described.