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Refinement of modulated structures against X‐ray powder diffraction data with JANA 2000
Author(s) -
Dušek M.,
Petříček V.,
Wunschel M.,
Dinnebier R. E.,
Van Smaalen S.
Publication year - 2001
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/s0021889801003302
Subject(s) - icosahedral symmetry , aperiodic graph , crystallography , diffraction , powder diffraction , crystal structure , x ray crystallography , rietveld refinement , materials science , molecule , position (finance) , electron diffraction , symmetry (geometry) , superstructure , x ray , chemistry , physics , optics , geometry , mathematics , thermodynamics , combinatorics , organic chemistry , finance , economics
JANA is a computer program for the refinement and analysis of periodic and aperiodic (incommensurately modulated structures and composite crystals) crystal structures. Here a new module is introduced that allows Rietveld refinements against powder diffraction data. It is shown that JANA 2000 provides a state‐of‐the‐art description of the peak profiles. A re‐analysis of the low‐temperature structure of (CO) x C 60 showed that the application of icosahedral symmetry restrictions to the C 60 molecule leads to a better description of the electron density and to a corrected position of the CO molecule as compared with a rigid‐body refinement. The incommensurately modulated structure of NbTe 4 has been successfully refined against X‐ray powder diffraction data. The structural parameters are equal to, but less accurate, than the parameters obtained from a single‐crystal study.