Dear Thierry and Alan, @Thierry: Thank you very much! This is a great solution.
@Alan: I agree that we should strive to use as few and as meaningful refinable parameters as reasonably possible, not just in Rietveld refinements but in all kinds of modelling. The task I’m engaged in now is to estimate crystallite sizes in Si particles that are produced along with a lot of non-crystalline stuff in a semi-industrial process. Taking more time to produce “clean samples” is therefore not an option (although it would surely be the best advice for a pure structure determination/refinement study). Since there are a lot of sample and time is an issue, I don’t have the luxury to spend a lot of efforts on the other features in each dataset; at least not for the moment. I’m therefore more than happy to take some shortcuts in the description of the non-Bragg parts of the data. Best regards, Magnus From: rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> On Behalf Of Alan W Hewat Sent: 25 April 2022 15:50 To: rietveld_l@ill.fr Subject: Re: Introduction of non-structural peaks in Fullprof Dear Thierry and Magnus. Introducing an extra pseudo-phase, and then editing out all the peaks you don't want, is ingenious, but is it really less work than creating a background file as Rietveld advocated? The whole idea of Rietveld was to refine only physically meaningful parameters. The more parameters you introduce, the less confidence you can have in any of them being physically meaningful, especially if you then have to constrain some of them. Alan ________________________________ Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from phone) alan.he...@neutronoptics.com<mailto:alan.he...@neutronoptics.com> +33.476984168 VAT:FR79499450856 http://NeutronOptics.com/hewat _______________________________ On Mon, 25 Apr 2022, 14:53 Thierry Roisnel, <thierry.rois...@univ-rennes1.fr<mailto:thierry.rois...@univ-rennes1.fr>> wrote: Dear Magnus, Here is a way to fit independent peaks in FullProf : 1. edit .pcr file and add for every independent peak an artificial phase to treat in Profile Matching refinement mode (Jbt=2 and Irf=0). You can use P m m m space group for example and adjust the a parameter to fit with the diffraction peak 2theta position, b and c parameters can have arbitrary values, smaller than a. So, the special reflection will have 1 0 0 indices. 2. add refinement of one special reflection (Nsp_Ref = 1) 3. Run FullProf and update .pcr file, to provide Irf = 2 4. edit the created xxn.hkl file ( n for phase #n) and remove all reflections excepted the first one (1 0 0) 5. edit .pcr file and refine peak position and profile parameters for the special reflection you want to fit. The .pcr file will look as follows : Phase #2 : fit a single peak ! !Nat Dis Ang Pr1 Pr2 Pr3 Jbt Irf Isy Str Furth ATZ Nvk Npr More 0 0 0 0.0 0.0 1.0 2 2 0 0 0 32516.641 0 7 1 ! !Jvi Jdi Hel Sol Mom Ter Brind RMua RMub RMuc Jtyp Nsp_Ref Ph_Shift N_Domains 0 0 0 0 0 0 1.0000 0.0000 0.0000 0.0000 0 1 0 0 ! ! P m m m <--Space group symbol !-------> Profile Parameters for Pattern # 1 ----> Phase # 2 ! Scale Shape1 Bov Str1 Str2 Str3 Strain-Model 0.1252800E-04 0.00000 0.00000 0.00000 0.00000 0.00000 0 0.00000 0.000 0.000 0.000 0.000 0.000 ! U V W X Y GauSiz LorSiz Size-Model 0.005115 -0.007545 0.020850 0.012780 0.020016 0.000000 0.000000 0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ! a b c alpha beta gamma #Cell Info 3.400000 0.500000 0.500000 90.000000 90.000000 90.000000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 ! Pref1 Pref2 Asy1 Asy2 Asy3 Asy4 S_L D_L 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.01849 0.02007 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ! Special reflections: ! h k l nvk D-HG^2 Cod_D-HG^2 D-HL Cod_D-HL Shift Cod_Shift Del_U/sig1 Code Del_Y/gam2 Code 1 0 0 0 0.0000 0.000 0.00000 0.000 0.00000 0.000 0.00000 0.000 0.00000 0.000 I hope you will success in what you want to do. Regards Thierry Roisnel Le 25/04/2022 à 11:18, Magnus Sørby a écrit : Hi, I’m playing with Fullprof again for the first time in many years since I’ve changed employer and lost my access to Topas. Is it possible to introduce independent peaks (i.e. peaks whose positions are not determined by a unit cell) with refinable positions, intensities and shapes in Fullprof? I’ve found this possibility very useful in Topas for dealing with features in the datasets that are not of interest and not possible to possible to describe with a crystalline phase e.g. diffuse scattering from an amorphous component. I’m aware of the option to include a self-defined background (.bac file) with refinable scale, but this is time-consuming workaround. Best regards, Magnus ---- Magnus H. Sørby, PhD Senior Scientist - Materials Science and Analytical Chemistry Cenate AS Norway ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com><mailto:alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr><mailto: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/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -- Thierry Roisnel Centre de Diffractométrie X (CDIFX) Institut des Sciences Chimiques de Rennes UMR6226 CNRS - Université de Rennes 1 Bât. 10B, p. 153 Campus de Beaulieu Avenue du Général Leclerc 35042 Rennes cedex, France Tél: 02 23 23 59 02 Email : thierry.rois...@univ-rennes1.fr<mailto:thierry.rois...@univ-rennes1.fr.fr> [Centre de Diffractométrie X, ISCR UMR6226]<http://www.cdifx.univ-rennes1.fr/> [ISCR UMR6226]<http://www.scienceschimiques.univ-rennes1.fr/> ________________________________ Membre de ЯÉCIPROCS [Réseau ЯÉCIPROCS]<http://www.cdifx.univ-rennes1.fr/RECIPROCS> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com<mailto:alan.he...@neutronoptics.com>> Send commands to <lists...@ill.fr<mailto: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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