Re: Misconduct

What is Rietveld refinement? Does "Rietveld" QPA exist? Hill & Howard (1987) titled "QPA from Neutron Powder Diffraction Data Using the Rietveld Method" and indeed they refined all structural parameters of their simple phases in binary mixtures, a methodical test of the approach. However,

Re: Misconduct

Dear Kurt. No, refining just cell parameters doesn't qualify as Rietveld refinement :-) Certainly Hill/Howard (1987) and Bish/Howard made important contributions to QPA, but there were earlier papers eg *Werner et al (1979) * https://scripts.iucr.org/cgi-bin/paper?a18098 that you might also referen

Re: Misconduct

Hi Alan, in general, I could agree your strict definition, reducing the term "structure refinement" to atomic coordinates as the main goal. Hm, "QPA profile refinement" sounds a bit diffuse. What about "QPA full pattern profile refinement", resp. "QPA whole powder pattern refinement"? Just t

[SUSPECTED SPAM] Re: Misconduct

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. Albe

Re: Misconduct

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 __

Re: Misconduct

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 t

Re: Misconduct

Yes Stefan, it is a question of what you are refining and constraining. Before Rietveld it was of course known that the positions of the peaks were determined by the unit cell. There were techniques like Search-Match that attempted to identify materials by the positions of the peaks. The history of

Re: Misconduct

Il 2024-01-16 16:21 Alan W Hewat ha scritto: And for those who worry about pedantry, "Rietveld Refinement" is just shorthand for the "Rietveld (method of) Refinement. It involves the refinement of the crystal structure, not Rietveld :-) Indeed! :-) Nonetheless, whatever the analysis, the profi

Re: Misconduct

"QPA Profile Refinement" is shorthand for "QPA (using the) Profile (method of) Refinement :-) Yes, it is the phase composition that is refined, by fitting the profile, but I see no problem with the shorthand expression. Dr Alan Hewat, NeutronOptics Grenoble, FRANC

Re: Misconduct/terminology

Dear Alan/All, I have a problem with that shorthand expression, particularly in teaching and training contexts, because students quickly equate this to “refining the data”. Countless research papers, even coming from reputable groups and published in reputable journals, contain statements that

Re: Misconduct/terminology

Potato-potato...Software that I am using for QPA has one button named "Rietveld refinemet" so for me it is Rietveld refinement 😀👍Poslano iz Outlook za Android ++ Please do NOT attach files to the whole list Send commands to eg: HELP as t

Re: Misconduct/terminology

Il 16/01/2024 17:06, EVANS, IVANA R. ha scritto: Dear All, Data shold be NEVER refined, no matter whether "data£ is considered singular or plural. It's the model which is refined. Beyound this, "data" is plural, as it is the plural of "datum". https://dictionary.cambridge.org/dictionary/english

RE: Misconduct/terminology

Bravo!!! James P. Cline Materials Measurement Science Division National Institute of Standards and Technology 100 Bureau Dr. stop 8370 [ B113 / Bldg 217 ] Gaithersburg, MD 20899-8523USA james.cl...@nist.gov https://www.nist.gov/people/james-p-cline (301) 975 5793

Re: Misconduct/terminology

Dear Smudut. Potatoes in gives Potatoes out from black box software with buttons. Dear Ivana. Do you also have a problem with the shorthand expression "Rietveld Refinement"? If so, you might try my joke that Rietveld is already refined :-) I think you can use such apparent mis-statements to teach

RE: [EXTERNAL] Re: Misconduct

I like Stefan’s view outlined below. In many cases, we will indeed refine those structural parameters to get the best possible match. But when I use a structural model so that I calculate F(hkl) values, and combine that with the ability to vary all kinds of parameters - some structure-related, s

Re: Misconduct

😂 That’s the best message of the year! I should remember it. Luca > On 16 Jan 2024, at 15:22, Alan W Hewat wrote: > > Ha ! When Terry Sabine proposed to call it Rietveld Refinement, I told him > that Rietveld was already "refined". > > > Dr Alan Hewat, Neu

Re: Misconduct/terminology

Dear Alan, No problems with “Rietveld refinement” at all, despite the fact that I met Hugo Rietveld when I was a young postdoc at 1999 IUCr and he seemed rather refined to me, too. And it’s not my students I’m concerned about - they take me surprisingly seriously, on issues of refinement and (c

Re: [EXTERNAL] Re: Misconduct

"In many cases, we will indeed refine those structural parameters to get the best possible match". The best possible match is not the objective of QPA, but rather the best possible estimation of the phase fractions. You can refine parameters describing particle size, strain, lattice constants, etc

RE: [EXTERNAL] Re: Misconduct/terminology

I should have been more specific – this was not with respect to QPA specifically – it was a more general statement about the terminology of when we should or shouldn’t use the expression “Rietveld refinement”. Although we actually often do Rietveld refinements on 2 phase mixtures, where one phas

Re: [EXTERNAL] Re: Misconduct/terminology

OK, thanks Cora. Yes, an internal standard using a simple well characterised material is a good idea. I perhaps over reacted when you listed all the parameters you refined for a multi-phase sample, including ADPs. Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from