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    ABSTRACT: The fuzzy frontiers between structure determination by powder diffractometry and crystal structure prediction are discussed. The application of a search-match program combined with a database of more than 60 000 predicted powder diffraction patterns is demonstrated. Immediate structure solution (before indexing) is shown to be possible by this method if the discrepancies between the predicted crystal structure cell parameters and the actual ones are < 1 %. Incomplete chemistry of the hypothetical models (missing interstitial cations, water molecules, etc.) is not necessarily a barrier to a successful identification (in spite of inducing large intensity errors), provided the search-match is made with chemical restrictions on the elements present in both the virtual and experimental compounds. (C) 2008 International Centre for Diffraction Data.
    Powder Diffraction 06/2008; 23(2):S5-S12. DOI:10.1154/1.2903488 · 0.59 Impact Factor
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    ABSTRACT: The information storage and retrieval system of x-ray phase identification (ISRS PI) targeted to determination of a substantial phase composition of complex and substantially multicomponent polycrystalline materials by their x-ray diffraction spectra is described. A base element of the system is a problem-oriented operator language of search queries for phase identification (PI). The identification procedure is performed with the use of a graphical interface that provides processing of x-ray powder diffraction patterns, self-programming and fulfillment of queries for PI hidden from the user, and construction of model spectra. The identification possibilities of ISRS PI (Retrieve QQPA) are discussed on the basis of data on the Search-Match Round Robin-2002 Internet competition carried out by the CPD Commission of the International Union of Crystallographers.
    Inorganic Materials 11/2008; 44(14):1531-1535. DOI:10.1134/S0020168508140082 · 0.51 Impact Factor
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    ABSTRACT: Databases dedicated to predicted inorganic crystal structures are emerging fast. Possible applications are listed, from identification through the powder diffraction pattern fingerprint, leading to crystal structure determination before estimation of the cell parameters of newly synthesized real compounds, to the prediction of interesting properties of still unknown materials, allowing chemical synthesis efforts to concentrate on definite targets. The limitations of such approaches due, in some cases, to the incompleteness and poor quality of the predictions and to the lack of openly available efficient tools are discussed through examples.
    Physical Chemistry Chemical Physics 08/2010; 12(30):8521-30. DOI:10.1039/c003907c · 4.20 Impact Factor