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On the determination of accurate intensities from powder diffraction data. I. Whole‐pattern fitting with a least‐squares procedure
Author(s) -
Jansen J.,
Peschar R.,
Schenk H.
Publication year - 1992
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/s0021889891012104
Subject(s) - intensity (physics) , diffraction , powder diffraction , curve fitting , least squares function approximation , materials science , analytical chemistry (journal) , chemistry , optics , crystallography , physics , mathematics , statistics , chromatography , estimator
A new algorithm, direct intensity fitting, has been developed which performs a whole‐pattern fitting for powder data. The algorithm is related to the fitting technique of Pawley [ J. Appl. Cryst. 14 , 357–361] but does not require start values for the intensities of the individual reflections. Comparative tests show that direct intensity fitting extracts more accurate intensities from a powder diffractogram and reduces the minimum peak distance for accurate data to half of the half‐widths. The structure of the superconductor Ba 2 YCu 3 O 8− x can be solved in a default direct‐methods run with direct‐intensity‐fitting intensities extracted from a normal laboratory powder diffractogram.