Abstract

Ab initio crystal structure determination from powder diffraction data is not yet a straightforward process: it is strongly disrupted by the low quality of the estimated Bragg reflection intensities. In a two-stage method the integrated intensities calculated from a powder pattern are immediately submitted to direct methods to obtain phases. The larger the accuracy of the integrated intensities, the more efficient the phasing process. A systematic decomposition procedure was introduced in the EXPO2004 program to improve the efficiency of the phasing process. The disadvantage of this approach is that a large number of feasible trial structures are generated, among which the correct solution must be recognized. A new procedure is described aiming at introducing strategies to reduce the total number of trials to explore by defining an appropriate figure of merit able to regroup trial structures into different batches, each element of a batch sharing a high percentage of atoms with the other elements of the same batch. The new figure of merit, implemented in an updated version of EXPO2009, is able to discriminate non-solutions from promising trials, corresponding to incomplete or rough models which evolve, after refinement, into the correct solution.

Autore Pugliese

• Altomare Angela , Moliterni Anna , Cuocci Corrado , Rizzi Rosanna

Tutti gli autori

• Altomare A.; Cuocci C.; Giacovazzo C.; Moliterni A.; Rizzi R.

Titolo volume/Rivista

Journal of applied crystallography

Anno di pubblicazione

2011

ISSN

0021-8898

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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