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Distribution rules of systematic absences and generalized de Wolff figures of merit applied to electron backscatter diffraction ab initio indexing
Author(s) -
Oishi-Tomiyasu Ryoko,
Tanaka Tomohito,
Nakagawa Jun'ichi
Publication year - 2021
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576721002120
Subject(s) - search engine indexing , figure of merit , ab initio , bravais lattice , orthorhombic crystal system , diffraction , physics , computer science , computational physics , crystallography , optics , chemistry , crystal structure , information retrieval , quantum mechanics
A new method for electron backscatter diffraction ab initio indexing is reported that adopts several methods originally invented for powder indexing. Distribution rules of systematic absences and error‐stable Bravais lattice determination are used to eliminate the negative influence of non‐visible bands and erroneous information from visible bands. In addition, generalized versions of the de Wolff figures of merit are proposed as a new sorting criterion for the obtained unit‐cell parameters, which can be used in both orientation determination and ab initio indexing from Kikuchi patterns. Computational results show that the new figures of merit work well, similar to the original de Wolff M n . The ambiguity of the indexing solutions is also pointed out, which happens in particular for low‐symmetry cells and may generate multiple distinct solutions even if very accurate positions of band centre lines and the projection centre are given. It is supposed that this is the reason why indexing was successful in an orthorhombic case but not in a triclinic cell.