Реферат: Powder Diffraction is a valuable tool when studying a statistical number of objects, e.g. in quantification or probing chemical reactions or phase transitions. It also provides information on many important compounds and materials that cannot be prepared as single crystals, or that, while starting as single crystals, become polycrystalline due to structural transformations on variations of temperature, pressure, irradiation, etc. Data analysis for powder diffraction is normally not only less straightforward then for single crystals, but is also more prone to ending in false minima and getting wrongly interpreted. A more delicate and possibly robust approach is needed to retrieve the correct information. It is therefore desirable, at times, to go back to original data and find out the origin of specific features in the data themselves, whether coming from the setup, from mishandling or from the experiment itself. This helps not only avoiding mistakes but also extracting the maximum information, which at times can only be viewed a posteriori after more knowledge on the system has been acquired. In this context correct data handling is pivotal to being able to successfully look back at ‘old’ but still valuable patterns. In the present contribution, we aim to define the important aspects in regulating powder diffraction raw data, including the level at which “raw is raw” and the metadata that needs to be included, to make sure enough information is kept. This, to ensure it is possible to look back successfully at previous data and/or correct problematic behavior. The discussion will involve both 1D and 2D detector datasets, including very large ones (several thousand patterns). As one of the examples, matching several aspects, we use a high-pressure study of phase transitions in L-Serine. We illustrate, how the raw data collected in 2006 [1] could be used almost 10 years later, in order to get new information from these data, viewed through the new experience obtained in 2015 [2]. [1] Boldyreva, E. V., Sowa, H., Seryotkin, Y. V., Drebushchak, T. N., Ahsbahs, H., Chernyshev, V., & Dmitriev, V. (2006). Pressure-induced phase transitions in crystalline L-serine studied by single-crystal and high-resolution powder X-ray diffraction. Chemical Physics Letters, 429(4-6), 474-478. [2] Fisch, M., Lanza, A., Boldyreva, E., Macchi, P., & Casati, N. (2015). Kinetic control of high-pressure solid-state phase transitions: A Case Study on L-serine. The Journal of Physical Chemistry C, 119(32), 18611-18617. EVB acknowledges funding from the Ministry of Science and Education RF (project AAAA-A21-121011390011-4).

Библиографическая ссылка: Casati N.P.M. , Boldyreva E.
Powder Diffraction Raw Data
Workshop on Raw diffraction data reuse: the good, the bad and the challenging 22-22 Aug 2023