You are both true in a certain sense. It is true that this is not the core of the Rietveld refinement per se, but we don’t have an “official” term to call a refinement of a powder pattern using crystallographic parameters. Hence I tried to call it Rietveld-like or extended Rietveld. The alternatives are full pattern fitting, but this is usually referring to an unconstrained refinement, Pawley like. In XRF they use the term Fundamental Parameters approach, but I am afraid in diffraction was already used (first Cohere, am I remembering right?) for fitting profiles using physical models for the instrumental broadening. The Rietveld community never defined a generally accepted term for this kind of refinement, so people outside it what can they use?
I am amused how Armel can spot such articles and especially notice the trick they did. I would not call the worse Rietveld refinement but for sure a bad misconduct case. Were they removing some peaks they could not explain or put down an amorphous halo at low angle? I am sad they used Maud in the first place and then manipulate the image. I notice that they report the intensity as (linear) counts, but it is not, they replaced also the labels as from the noise, residual and peaks intensity I am sure it was in square root of the intensity. Background was removed too. But I think there was no review at all, as the figure caption contains errors even for the chemical formula (Fe -> F). Best regards, <http://www.unitn.it/> Luca Lutterotti Dipartimento di Ingegneria Industriale Università di Trento via Sommarive, 9 - 38123 Trento (Italy) tel. +39 0461 2824-14 (Office), -34 (X-Ray lab)  Maud: http://maud.radiographema.com <http://maud.radiographema/> > On 13 Jan 2024, at 07:39, Alan W Hewat <alan.he...@neutronoptics.com> wrote: > > The core of Rietveld refinement is REFINING the crystallographic parameters > to fit the pattern. That was the great innovation. Is that done here ? To > calculate various patterns to refine phase composition you necessarily need > models of the crystal structures. But all refinements of powder patterns are > not Rietveld Refinement. Quantitative analysis of powder samples is an > important technique, and to attribute that to Rietveld is wrong. Same goes > for Pair Distribution Function analysis. Calling everything "Rietveld > Refinement" is not helpful, and actually hides the fundamental contribution > of this technique to crystallography. > > ________________________________ > Dr Alan Hewat, NeutronOptics > Grenoble, FRANCE (from phone) > alan.he...@neutronoptics.com > +33.476984168 VAT:FR79499450856 > http://NeutronOptics.com/hewat <http://neutronoptics.com/hewat> > _______________________________ > > > On Sat, 13 Jan 2024, 07:00 Matthew Rowles, <rowle...@gmail.com > <mailto:rowle...@gmail.com>> wrote: >> Hard disagree here. >> >> You're using crystallographic parameters to calculate the (intensities and >> positions of the) pattern. >> >> To me, that's the core of Rietveld refinement. >> >> You need to apply a peak shape model. Why not apply a model from which you >> can extract crystallite parameters? >> >> QPA can then be done on the output of a refinement, eg application of the >> internal standard method using the Hill /Howard algorithm. >> >> Its still a Rietveld refinement, I'm not just fitting peaks willy nilly; >> they're constrained by a crystal model. >> >> >> Matthew >> >> On Sat, 13 Jan 2024, 01:48 Alan W Hewat, <alan.he...@neutronoptics.com >> <mailto:alan.he...@neutronoptics.com>> wrote: >>> Apart from the record number of atoms, phases, parameters, citations etc >>> used to describe just 3 broad peaks, I object to this kind of refinement >>> being called "Rietveld refinement". Luca called it "Rietveld-like" in MAUD, >>> which was used here, but even that is wrong. The term "Rietveld refinement" >>> should be restricted to the refinement of crystallographic parameters - >>> cell dimensions, atom coordinates etc. and not applied to quantitative >>> analysis of phases, particle size etc. Fitting peaks in powder patterns was >>> done before Rietveld, who must be turning in his grave to see his name >>> associated with this kind of thing. >>> >>> ________________________________ >>> Dr Alan Hewat, NeutronOptics >>> Grenoble, FRANCE (from phone) >>> alan.he...@neutronoptics.com >>> +33.476984168 VAT:FR79499450856 >>> http://NeutronOptics.com/hewat <http://neutronoptics.com/hewat> >>> _______________________________ >>> >>> >>> On Fri, 12 Jan 2024, 12:57 Le Bail Armel, <le-bail.ar...@orange.fr >>> <mailto:le-bail.ar...@orange.fr>> wrote: >>>> Hi, >>>> >>>> A good candidate for the "worst Rietveld refinement of the year" award : >>>> >>>> https://pubpeer.com/publications/12069A6AD9D5D34F26031F34705D06 >>>> >>>> Even the difference pattern is totally fabricated. >>>> >>>> Best >>>> >>>> Armel >>>> >>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> Please do NOT attach files to the whole list <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/ >>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> >>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>> Please do NOT attach files to the whole list <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/ >>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 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/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 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/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
