@AFC_cristal
16-21 octobre 2022, Grenoble
inscription available at
https://workshops.ill.fr/e/add2022
The ADD2022 School and Conference aim to deepen the understanding and to further the training of the various communities working on real-space data analysis for neutron and x-ray diffraction techniques. Fourier transformation of diffraction data into real-space, traditionally used for the structural determination of liquids and glasses, is now increasingly employed for partially-disordered crystalline powder samples, as well as for single-crystal samples exhibiting some local atomic disorder, and most recently for short-range spin-spin correlations in disordered or frustrated magnetic systems (in the case of neutron diffraction).
The scientific scope of ADD2022 pertains to both x-ray and neutron diffraction techniques, and will again include single-crystal diffuse scattering as an integral part of the School and the Conference. Note that we also welcome presentations and participants in the field of e-beam diffraction having real-space analysis techniques. The School proposes pedagogic lectures on real-space data-analysis techniques followed by 9 separate sessions of hands-on tutorials for training with various data-modelling software packages: DiffPy-CMI, diffpy.mpdf, DISCUS, Dissolve, EPSR, PDFgui, RMCProfile, Spinvert and Yell. The Conference proposes 8 invited talks and about 16 additional oral contributions, as well as a poster session.
The Fourier transformation of diffraction data into real-space produces a Pair-Distribution Function (PDF) that provides a model-independent "snapshot" of the local structure within the sample. The PDF(r) thus probes both static and dynamic atomic correlations (and also magnetic spin-spin correlations in the case of neutron diffraction). The so-called "PDF-analysis" technique is therefore complementary to the well-known Rietveld method of refining diffraction data in Q-space that provides a space-time averaged picture of the sample's structure. PDF-analysis now enjoys a wide field of application, in particular to nano-structured materials.
Building on the success of our previous ADD workshops in Grenoble (ADD2019 of 17-22 March 2019, ADD2016 of 7-11 March 2016, ADD2013 of 18-22 March 2013, ADD2011 of 12-14 October 2011), the ADD2019 School+Conference will start Sunday evening 16 October 2022 and finish Friday afternoon 21 October, a full 5-day programme that includes 2-1/2 days for the School followed by 2-1/2 days for the Conference, basically the same format as for ADD2019.
As compared to ADD2019, the 2022 edition includes two additional hands-on tutorials: (1) Dissolve, which builds on the success of EPSR and employs similar techniques, but utilises a full classical forcefield and is extensible to multi-configuration, million-atom simulations, and (2) diffpy.mpdf, which as an extension module of DiffPy-CMI allows for real-space modeling of local magnetic spin correlations.
And as for ADD2019, ADD2022 also features pedagogic lectures on nitty-gritty data-reduction and data-correction techniques for x-ray and neutron diffraction as concerns liquids/glasses, disordered crystals and single-crystal diffuse scattering.
Real-space analysis of diffraction data deals with general structural concepts such as atomic/spin distribution functions and structural/magnetic correlation lengths, and now employs standard formulae common to neutron, x-ray and other diffraction techniques. It therefore facilitates a synergetic convergence of hitherto largely disjoint communities: liquids/glasses diffraction, crystalline powder diffraction, single-crystal diffuse scattering and diffuse magnetic scattering.