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Determination of the β‐quartz hexagonal cell parameters from a 00.1 neutron multiple diffraction Umweganregung pattern measured at 1003 K
Author(s) -
De Campos Luiz Carlos,
Parente Carlos Benedicto Ramos,
Mazzocchi Vera Lucia
Publication year - 2010
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/s0021889810037969
Subject(s) - quartz , neutron diffraction , diffraction , materials science , azimuth , hexagonal crystal system , neutron , analytical chemistry (journal) , mathematics , physics , optics , crystallography , chemistry , nuclear physics , chromatography , composite material
The hexagonal cell parameters a and c of β‐quartz have been determined from a 00.1 β‐quartz neutron multiple diffraction Umweganregung pattern measured at 1003 K. Owing to the high density of multiple diffraction peaks in the indexing of the pattern, contrasting with the low density of experimental peaks, a procedure to correctly index peaks has first been applied. After the correct indexing, the peaks were selected taking into account their quality (adequate intensity and definition) and then classified in accordance with their suitability for the determination of a or c . The azimuthal angular positions of classified peaks were applied to indexing diagrams in order to obtain sets of values for both a and c . Weighted means of the sets give final values for a and c . In order to obtain more reliable final values an iterative process has been employed. A statistical analysis of data has also been employed to calculate uncertainties for the mean values found in the iterative process. After 12 cycles of iteration, the results converged to a = 4.9957 (14) and c = 5.46184 (35) Å for β‐quartz at 1003 K.