Hi Francois Reflection mode at a synchrotron? Does that mean you have the beam coming in at a fixed angle with respect to the specimen, and then collecting all the angles?
Because of the change in specimen volume with angle, you need to modify the calculated intensities, as most (all?) Rietveld programs assume constant volume. Have a look at a previous paper of mine https://espace.curtin.edu.au/handle/20.500.11937/50104 and in particular, §2.1 Flat-plate asymmetric reflection. Hope it all makes sense Matthew On Wed, 27 Mar 2024 at 22:24, francois Goutenoire < francois.gouteno...@univ-lemans.fr> wrote: > Dear Rietveld users > > I have some data collected on a synchrotron line on reflection mode. > > The sample is an ancient steel (Fe alpha + Fe3C). The aim is to analyzed > Fe/Fe3C in order to get the carbon content. > > The total scattering volume is obviously not constant with 2 theta. > > We can observe an increase of the background and the Rietveld refinement > is not possible, but the Le Bail fit is good (see on the link). > > In order to get a good Rietveld refinement, I would like to modified the > data (Sorry !! I known is not acceptable ! Joke). > > The idea is to use the background to modified the intensities, in order to > get a flat background. > > I would like to use the Legendre polynomials coefficients to do this > correction. > > Does someone know how to to that ? > > Link for the images https://perso.univ-lemans.fr/~fgouten/Legendre > > Best wishes, francois > > -- > ********************************************************************************************* > Pr. Francois GOUTENOIRE > e-mail: francois.gouteno...@univ-lemans.fr > Tel: 02.43.83.33.54 > FAX: 02.43.83.35.06 > Institut des Molécules et des Matériaux du Mans > IMMM - UMR CNRS 6283 > Elaboration et Caracterisation des Composés Cristalisés (E3C) > Université du Maine - Avenue Olivier Messiaen > F-72085 Le Mans Cedex 9 > FRANCE > ********************************************************************************************* > Formation Rietveld > CNRShttps://cnrsformation.cnrs.fr/diffraction-des-rayons-x-sur-materiaux-polycristallins?axe=135 > Formation EDX CNRShttps://cnrsformation.cnrs.fr/fluorescence-x-edx?axe=135 > Formation SAXS et Réflectivités pour couches minces et matériaux > nanostructurés.https://cnrsformation.cnrs.fr/caracterisation-des-materiaux-nanostructures-par-diffusion-des-rayons-x?axe=135 > Bibliographiehttps://scholar.google.fr/citations?hl=fr&user=qC-lmN4AAAAJ&view_op=list_works&authuser=1&sortby=titlehttps://orcid.org/0000-0001-5339-3002 > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > >
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