Dear Alan,
I agree completely, especially with the evaluation of the "quality" of
the paper triggering the discussion.
Regarding misleading and capturing terminology in analytical methods,
I have an IMHO more serious, horrible example:
"Automated mineralogy"
https://en.wikipedia.org/wiki/Automated_mineralogy
what is very popular in a big community of geologists and aggressively
advertised, despite of nether any chemometric evaluation by
interlabory tests was published, phase abundances are given to second
to forth decimal digit of mass% and analytical errors resp. esd's are
typically not published. But even here we probably have already lost
the battle for precise terminology and quality of analytics, as people
can present such data and terminology in several journals of applied
geology and mineral processing without any problem.
Reinhard
Zitat von Alan W Hewat <alan.he...@neutronoptics.com>:
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 phase analysis is older than Rietveld. The Petten group were not
interested in QPA, but instead in refining the crystal and magnetic
structures of specific materials.
If Rietveld had never existed, it is reasonable to assume that QPA would
still have evolved much as it has today, refining the phase content from
the whole profile, without trying to refine structures of mixed phases.
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 :-)
Finally Kurt, perhaps as individuals we can't change the world, but if we
are concerned that people are debasing our scientific techniques, we can
expose them as Armel did. Or at least we can refuse to co-author such
papers, and reject them as journal editors. As authors and referees we can
correct sloppy use of terminology. This paper is wrong on so many levels,
apart from the apparent "misconduct" and the incorrect label of Rietveld
Refinement.
________________________________
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, 15:50 Stefan Seidlmayer, <ste...@seidlmayer.de> wrote:
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/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
--
TU Bergakademie Freiberg
Dr. R. Kleeberg
Mineralogisches Labor
Brennhausgasse 14
D-09596 Freiberg
Tel. ++49 (0) 3731-39-3244
Fax. ++49 (0) 3731-39-3129
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
