Interpretatsiya poroshkovikh rentgenogramm polykristallov s primeneniem elektronno-vichislitelnikh mashin (EVM). I. Programma dlya srednik kristallicheskikh sistem

The use of a BECM-4 computer is described for interpreting X-ray powder patterns of polycrystals belonging to the tetragonal, hexagonal or rhombohedral systems after Neskuchaev's technique. A program is proposed for direct indexing and the determination of crystal lattice parameters from the X-ray powder pattern diffraction data of polycrystals belonging to these crystalline systems. The program is designed to make optimal use of the machine time. A block-diagram shows the complete procedure for the computations. The program has been tested by application to the X-ray powder diffraction pattern of calcium tungstate (scheelite), CaWO₄, lead phosphate hydroxide, Pb₅(PO₄)₃OH, and nickel fluorosilicate hexahydrate, NiSiF₆.6H₂O. Twenty or thirty experimental values are used for the computations. The average period between the experimental data input and the results output corresponds to ten minutes of machine time. Computations by the programming technique suggested are neither complicated nor laborious.