Use of high-symmetry zone axes in electron diffraction in determining crystal point and space groups

Abstract

A sequence of steps is given for making use of the information available on convergent-beam electron diffraction patterns from high-symmetry zone axes for crystal point-and space-group determination.

Space-group determination and structure model for κ-Al2O3 by convergent-beam electron diffraction (CBED)

“…The occurrence of these dynamical absences in kinematically forbidden reflections can be used to confirm the presence of screw axes and glide planes in the structure. In the present case, it is the existence of a 21 screw axis along the c axis (Steeds & Vincent, 1983;Tanaka & Terauchi, 1985;Tanaka, Terauchi & Kaneyama, 1988 Fig. 9, it can be seen in the ZOLZ that there are G-M lines in the discs of (001) where / is an odd number.…”

Revised structure of Bi3TiNbO9

“…2a) and m whole-pattern symmetries (see Fig. 2b) thus confirming a 2ram crystal point-group symmetry (Steeds & Vincent, 1983). That the Bravais lattice is A-centred is clear from [001] zone-axis selected-area electron diffraction patterns (SADP's) (see Fig.…”

Tribocorrosion damage of a Jethete M152 type stainless steel

“…The WP symmetry is the symmetry of the HOLZ lines and zero-order-Laue-zone (ZOLZ) Kikuchi lines in the pattern as a whole. From the BF and WP symmetries of CBED patterns obtained from several prominent zone axes, it is possible to find one of 31 diffraction groups, and then the possible point group, based on Steeds and co-worker's work [3,4]. A [001] zone CBED pattern is shown in Fig.…”