Abstract

Modulated enhanced diffraction (MED) is a technique allowing the dynamicstructural characterization of crystalline materials subjected to an externalstimulus, which is particularly suited for in situ and operando structuralinvestigations at synchrotron sources. Contributions from the (active) part of thecrystal system that varies synchronously with the stimulus can be extracted by anoffline analysis, which can only be applied in the case of periodic stimuli andlinear system responses. In this paper a new decomposition approach based onmultivariate analysis is proposed. The standard principal component analysis(PCA) is adapted to treat MED data: specific figures of merit based on theirscores and loadings are found, and the directions of the principal componentsobtained by PCA are modified to maximize such figures of merit. As a result, ageneral method to decompose MED data, called optimum constrainedcomponents rotation (OCCR), is developed, which produces very preciseresults on simulated data, even in the case of nonperiodic stimuli and/ornonlinear responses. The multivariate analysis approach is able to supply in oneshot both the diffraction pattern related to the active atoms (through the OCCRloadings) and the time dependence of the system response (through the OCCRscores). When applied to real data, OCCR was able to supply only the latterinformation, as the former was hindered by changes in abundances of differentcrystal phases, which occurred besides structural variations in the specific caseconsidered. To develop a decomposition procedure able to cope with thiscombined effect represents the next challenge in MED analysis.

Autore Pugliese

• Caliandro Rocco , Nico Giovanni

Tutti gli autori

• R. Caliandro; P. Guccione; G. Nico; G. Tutuncu; J.C. Hanson

Titolo volume/Rivista

Journal of applied crystallography

Anno di pubblicazione

2015

ISSN

1600-5767

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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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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