Institute of Crystallography - CNR

Stimulus-response studies on materials through in situ / operando crystallographic measurements and multivariate analysis

The experimental study of the structural dynamics of crystalline or amorphous compounds is addressed using X-ray experiments in situ / operando and analyzing the data collected according to multivariate analysis procedures. The developed algorithms are implemented in the software RootProf.

The design of materials and advanced manufacturing requires in-depth knowledge of the structural response of materials to external stimuli such as temperature, pressure, mechanical stress, lighting, electromagnetic fields, exposure to gas flows or solvents. The structural dynamics of compounds in the crystalline state can be acquired by carrying out X-ray experiments in situ, during which the sample, while subjected to an external stimulus, even variable, is subjected to repeated measurements of X-ray diffraction. The sample can also be placed in the working conditions during the experiment, allowing its structural characterization in operating conditions. Nano-structured, quasi-crystalline or amorphous compounds can be studied using X-ray diffraction techniques such as the Pair Distribution Function (PDF), sensitive to the local order. The execution of in situ / operando experiments is coupled with advanced and fast calculation methods to cope with the huge amount of data collected and to extract valuable information hidden in the data through an analysis without models. Data analysis approaches based on multivariate analysis are developed that are independent of the type of interaction used for the experimental investigation and are able to efficiently process multiple measures, considering them as an entire data matrix. We have developed a set of fully automatic calculation procedures for big-data based on the analysis of the principal components, capable of extracting qualitative and quantitative information.

Reference works

– Investigating temperature-induced structural changes of lead halide perovskites by in situ X-ray powder diffraction
R Caliandro, D Altamura, BD Belviso, A Rizzo, S Masi, C Giannini (2019) Journal of Applied Crystallography 52 (5), 1104-1118

– Principal component analysis for automatic extraction of solid-state kinetics from combined in situ experiments
P Guccione, L Palin, BD Belviso, M Milanesio, R Caliandro (2018) Physical Chemistry Chemical Physics 20 (29), 19560-19571

– Improved multivariate analysis for fast and selective monitoring of structural dynamics by in situ X-ray powder diffraction
P Guccione, L Palin, M Milanesio, BD Belviso, R Caliandro (2018) Physical Chemistry Chemical Physics 20 (4), 2175-2187

– RootProf: Software for multivariate analysis of unidimensional profiles
R Caliandro, DB Belviso (2014) Journal of Applied Crystallography 47 (3), 1087-1096