Bravais lattice determination from a single CBED pattern

Abstract

Traditional methods for Bravais lattice determination of unknown materials using electron diffraction involve symmetry determination from several low index zone axis diffraction patterns, measuring the distances between spots or disks and indexing them by trial and error method. Such methods are ofte repetitive, error prone and difficult, if not impossible, for low-symmetry crystals. Thus a simpler, accurate, and automated method for lattice determination is highly desirable in electron diffraction. Here new method of Bravais lattice determination using an arbitrary single convergent beam diffraction (CBED pattern is summarized. A full description of the method has been submitted for elsewhere. The method uses the deficiency lines of high order and high order Laue zone (HOLZ) reflections to measure the primitive cell of the zone axis, and use the standard Krivy and Gruber procedure to reduce this arbitrary primitive cell to a unique Niggli cell, and thus the Bravais cell.