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SHELXT – Integrated space‐group and crystal‐structure determination
Author(s) -
Sheldrick George M.
Publication year - 2015
Publication title -
acta crystallographica section a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.742
H-Index - 83
ISSN - 2053-2733
DOI - 10.1107/s2053273314026370
Subject(s) - group (periodic table) , space (punctuation) , space group , crystal structure , isotropy , data structure , unit (ring theory) , inversion (geology) , reflection (computer programming) , crystallography , group structure , mathematics , computer science , physics , chemistry , optics , quantum mechanics , diffraction , x ray crystallography , psychology , paleontology , programming language , mathematics education , structural basin , psychotherapist , biology , operating system
The new computer program SHELXT employs a novel dual‐space algorithm to solve the phase problem for single‐crystal reflection data expanded to the space group P 1. Missing data are taken into account and the resolution extended if necessary. All space groups in the specified Laue group are tested to find which are consistent with the P 1 phases. After applying the resulting origin shifts and space‐group symmetry, the solutions are subject to further dual‐space recycling followed by a peak search and summation of the electron density around each peak. Elements are assigned to give the best fit to the integrated peak densities and if necessary additional elements are considered. An isotropic refinement is followed for non‐centrosymmetric space groups by the calculation of a Flack parameter and, if appropriate, inversion of the structure. The structure is assembled to maximize its connectivity and centred optimally in the unit cell. SHELXT has already solved many thousand structures with a high success rate, and is optimized for multiprocessor computers. It is, however, unsuitable for severely disordered and twinned structures because it is based on the assumption that the structure consists of atoms.