Whole Powder Pattern Decomposition

Uvarov and Popov [20] reported the quantification of polymorphic forms I and II using two different XRPD methods. One method was based on the single peak intensity or direct method, and the second used whole-powder-pattern decomposition (WPPD) method. The Form-I nonoverlapping peaks suitable for analysis work were found at d-spacings 8.13, 5.98, and 4.32 A, while the useful peaks for Form-II had d-spacings of 7.24 and 6.88 A. It was shown that use of the WPPD method yielded better... 

Whole Powder-Pattern Decomposition Methods (WPPD). In WPPD the... 

When a peak is large, this may become quite significant,"" " including in the case of whole powder pattern decomposition detailed in the next section. 

WHOLE POWDER PATTERN DECOMPOSITION (WPPD) -NO STRUCTURE... 

Cell-restrained Whole Powder Pattern Decomposition... 

LEB 05] LEBAIL A., Whole powder pattern decomposition methods and applications a TctiospesAiwc , Powder Diffraction, vol. 20, p. 316-326,2005. 

An alternative approach to mixtures that contain phases with unknown or imperfectly known crystal structures combines the whole-powder-pattern-decomposition method with the Rietveld analysis. The method includes a modification of the standard Rietveld approach. 

The view about line profile analysis given in this chapter is pessimistic, it is the consequence of the complexity of the Bragg peak shapes as they occur from poorly-crystallized material. More optimistic is the future of the main whole powder pattern fitting applications (decomposition or Rietveld methods) that have moved beyond the initial stages, enabling structure determinations (almost routinely) and refinements (routinely) of moderately complex structures to even complex crystal structures such as proteins (sometimes). 

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