Dear all, I was following the discussion also with great interest, as terminology is important to distinguish properly between different items.
To my understanding the Rietveld approach was new because it constrained the fitting of a peak list generated "from a structure" with the refinement of the profile of the peaks themselves. Thus I would have the impression that everytime when we use a constrainement of peak list which is generated from a structure and do not refine a list of "individual peaks" it is a Rietveld-type refinement. A Profile Refinement is/was in my current understanding, when the peak/reflection position is not constrained by the structure parameters, but can be refined in an arbitrary way, individual for each peak/reflection. >From the positions refined in this way, one could then determine cell parameter etc. But this would require a secondary step. First refine all found peaks/reflection with a common profile. Then determine the lattice parameters from the refined peak positions etc. This is also troublesome as without prior structure "knowledge" it may and surely is that certain reflection which in fact are overlapping multiple reflections are improperly identified as "one" reflection. This is very the neatness of the Rietveld approach comes into play, as it generates even overlapping reflections which then generate the total profile by constraining them with the profile parameters. So the main point in differentiation is then in my eyes: Rietveld-Refinement: The use of a structure generated peak list which is constrained with profile parameters. Profile-Refinement: Profile refinement can work on individual peaks with NO structure information at all. Pawley-Refinement then is logically a little bit of a Hybrid, as the reflection list is pre-generated from the structure. But the intensities are just matched to best fit the profile. While in a true Rietveld even the reflection intensities is always generated from the underlying structure model applied in the Rietveld refinement. What do you think of this point of view? Am I overlooking something? Best regards Stefan Seidlmayer Am Di., 16. Jan. 2024 um 15:23 Uhr schrieb Alan W Hewat < alan.he...@neutronoptics.com>: > Ha ! When Terry Sabine proposed to call it Rietveld Refinement, I told him > that Rietveld was already "refined". > > ________________________________ > Dr Alan Hewat, NeutronOptics > Grenoble, FRANCE (from phone) > alan.he...@neutronoptics.com > +33.476984168 VAT:FR79499450856 > http://NeutronOptics.com/hewat > _______________________________ > > > On Tue, 16 Jan 2024, 15:11 , <alberto.martine...@spin.cnr.it> wrote: > >> Dear all, >> >> I'm following this interesting discussion. It seems to me that sometimes >> there is an improper use of terminology, in particular when we talk >> about "profile refinement"; in reality, we all know that it is about >> "profile fitting". Or did I miss something? >> >> sorry for the pedantry. >> Alberto >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 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/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > >
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 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/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
