Re: Misconduct

[Le Bail Armel]

Retracted :https://link.springer.com/article/10.1038/s41598-024-57685-9envoyé : 15 janvier 2024 à 20:05de : Le Bail Armel à : Le Bail Armel objet : Re: MisconductFrightening.Searching for “Rietveld refinement” in Google Scholar for 2024 gives already >1300 entries. Among the first 30 in the list, 3 show image manipulations (10%).Here is the third:https://pubpeer.com/publications/D73F5F6BA8C67E6F891F25D9A25790#1BestALBenvoyé : 12 janvier 2024 à 12:57de : Le Bail Armel à : Rietveld_L objet : MisconductHi,A good candidate for the "worst Rietveld refinement of the year" award :https://pubpeer.com/publications/12069A6AD9D5D34F26031F34705D06Even the difference pattern is totally fabricated.BestArmel ++ Please do NOT attach files to the whole list Send commands to 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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Re: Misconduct

[Le Bail Armel]

Good new from PubPeer:Virgil OptasanuHi. I am one of the co-authors. Thanks for these warnings. It does indeed appear that there are problems with this image with an intention to manipulate data. Whatever the reason for this manipulation, it is completely unacceptable. I will investigate to find the origin of this problem and ask the editors to possibly remove the article. Greetings.envoyé : 12 janvier 2024 à 12:57de : Le Bail Armel à : Rietveld_L objet : MisconductHi,A good candidate for the "worst Rietveld refinement of the year" award :https://pubpeer.com/publications/12069A6AD9D5D34F26031F34705D06Even the difference pattern is totally fabricated.BestArmel ++ Please do NOT attach files to the whole list Send commands to 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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Misconduct

[Le Bail Armel]

Hi,A good candidate for the "worst Rietveld refinement of the year" award :https://pubpeer.com/publications/12069A6AD9D5D34F26031F34705D06Even the difference pattern is totally fabricated.BestArmel
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Re: Step-like basline

[Le Bail Armel]

The muscovite data is dated 1996 from an old Philips 1710 diffractometer,vertical sample holder, scintillation counter, not much used because wehad better instruments, hence this stupid test ;-)Armelenvoyé : 7 septembre 2023 à 10:57de : Reinhard Kleeberg à : rietveld_l@ill.frobjet : Re: Step-like baslineDear Luca,sorry, I don't understand the "mosaic crystal" eplanation, especially not the "non-centre position" issue. IMHO, when the pattern was measured at a "powder" Bragg-Brentano configuration, in reflection mode, axial and equatorial divergence maximum ~ 2 degree, the 00l series of all misoriented crystal blocks can fulfill the diffraction condition only within the range of the instruments divergence, and the parafocusing arrangement would reflect such blocks back very close to the nominal angular position (as it is the case for a powder as well). So single crystal reflection of big blocks should only be observable within the total profile of a "normal" ideal powder peak (the "instrumental" profile"). This is indeed what we see if coarsely crystalline materials (e.g. quartz sand) are measured on a typical powder diffractometer: Such peaks are extremely sharp, sometimes split or doubled, sometimes with "wrong" alpha1/2 intensity ratio, or may have small additional maxima and may be "edges" in their slopes, depending on the number or size of crystals, but all these effects are very close to the correct maximum position (+- <1 degree). So I can't imagine that the unknown satellites in the mica pattern are "misoriented-displaced" Cu Kalpha 00l peaks?Armel, what type of detector was used for this measurement? If the W L series was detected, probably no diffracted beam monochromator, and no Peltier cooled Si drift detector? If so, even more spectral contamination may come into account. For example, I remember to have complained about a new Co tube (no company names here) showing systematic satellites ~ 1 % intensity from standard Si and LaB6 powder measurements. The wavelength recalculated by Bragg's law was Zn Kalpha (!!!), confirmed by spectral analysis, the tube Co target was obviously contaminated. As the satellites in your example in the < 0.x % magnitude of the Cu K alpha1 intensity, even quite low contamination of other elements than W may be the source. So it could be interesting to calculate wavelengths from all positions of the unknown satellites for the d-spacings of the mica 00l series and see if any calculated wavelengths do repeat.Another thought:Here we have a single crystal of muscovite. As some of the unexplained peaks appear to be extremely sharp, what about Renninger (multiple diffraction) hkl peaks? Maybe there are enough lattice planes in the monoclinic mica structure to give a chance for multiple diffraction to get registered by a divergent beam (Bragg-Brentano) configuration? Such peak positions appear to be unsystematic, with no relatiion to the Cu Kalpha 00l.However, a take-home message of your example should be: Do never measure single crystals in parafocusing geometry without safely monochromatic radiation ;-)Best regardsReinhardZitat von Luca Lutterotti :It is call graininess, as Miguel said before, these are mosaic single crystals and depending on your source (divergence, spot dimension at different angles etc.) you get each mosaic crystal to create a diffraction peak that especially at low two-theta angle may be displaced a lot from its theoretical position because it is diffracting from a non center position. This is what you get also when you analyse samples with extremely large grains. If you use a 2D detector instead of scanning with a point or small psd, you will see all these individual grain or mosaic crystals diffracting around their ideal spot or if it is a sample with just large grains, distributed around the Laue circle. More the grain is on a lateral position respect to the center of the beam, more it is displaced in two-theta. At higher angle your beam size on the sample is smaller and there is less displacement for geometrical reasons.I like to work with 2D detectors (texture, stresses) because it is easy to see these “figures”.In addition you have the spectral impurities identified by Frank and you may get some small grains with different orientation and twins that will create some of the non 00l peaks.Analysing these kind of patterns would require a sophisticated simulation of the grains-crystals distribution and computing like ray-tracing for the geometrical effects. Not worth it. Single crystals and sharp textures requires a point beam to avoid these effects. And a monochromatic one.Best regards,Luca Luca LutterottiDipartimento di Ingegneria IndustrialeUniversità di Trentovia Sommarive, 9 - 38123 Trento (Italy)tel. +39 0461 2824-14 (Office), -34 (X-Ray lab)Maud: http://maud.radiographema.com >> On 6 Sep 2023, at 17:43, Le Bail Armel  wrote:>>>> D

Re: Step-like basline

[Le Bail Armel]

Dear Frank,Same as you. I have not a complete solution.BestArmelenvoyé : 6 septembre 2023 à 16:57de : Frank Girgsdies à : Le Bail Armel Cc: Rietveld_L objet : Re: Step-like baslineDear Armel,Thanks for this nice quiz!However, after identifying the following spectral impurities: Cu K_beta, W L_alpha1,2 W L_beta1,2,3,4 and W L_gamma1,I am stuck now, leaving bout 1/2 to 1/3 of the tiny extra peaks unexplained.Some of them look suspiciously like Cu K_alpha1+2 doublets and might thus belong to an impurity phase, or differently oriented crystallites of the main phase, which could lie as dust on the single crystal surface, but I had no luck trying to identify them.Furthermore, the irregular high angle tailing of the 00l series (maybe stacking faults?) makes peak fitting difficult.Thus, I give up (at least for now), hoping that you might disclose the solution to the riddle, as far as it is known, for us after a while.Best wishes,FrankOn 06.09.2023 10:47, Le Bail Armel wrote:Hi,In the same subject.A special "powder pattern" to play with (try to explain all peaks) :http://cristal.org/muscovite.pdf BestArmel++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++>
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HiCANS (Hight Current Accelerator-driven Neutron Source)

[Le Bail Armel]

Interesting document about neutrons in French, though the word "Rietveld"appears only once, page 162, the word "poudre" (=powder) is more frequent :https://2fdn.cnrs.fr/wp-content/uploads/2023/09/ICONE-digital.pdf
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Re: Step-like basline

[Le Bail Armel]

Hi,In the same subject.A special "powder pattern" to play with (try to explain all peaks) :http://cristal.org/muscovite.pdfBestArmel
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Re: Rietveld condamnation considered as established by some more people

[Le Bail Armel]

Indeed, saying "back to that" with some disdain reveals your are the physicist interested by properties of already structurally known compounds.The crystallographer says "towards the posibility to solve the structure of unknowncompounds" and for that you need the structure factors. Then comes the Rietveld refinement anyway.envoyé : 18 août 2023 à 17:00de : Alan W Hewat à : Le Bail Armel cc : "rietveld_l@ill.fr" objet : Re: Rietveld condamnation considered as established by some more peopleI have no problem with Rietveld's prize Armel. Crystallographers ignored the method for too long, fixated as they were on "structure factors". Even your own method harks back to that. The idea that physical parameters could be refined directly from the data is more a physicist's idea, which makes me think that physicists Loopstra and Van Laar had essential input. Rietveld was a crystallographer. In retrospect the prize might have been awarded to the trio, but in retrospect we also simplify reality.Dr Alan Hewat, NeutronOpticsGrenoble, FRANCE (from phone)alan.he...@neutronoptics.com+33.476984168 VAT:FR79499450856http://NeutronOptics.com/hewat_______   On Fri, 18 Aug 2023, 15:15 Le Bail Armel, <le-bail.ar...@orange.fr> wrote:I would be curious if the Royal Swedish Academy of Sciences has archivesconcerning this Gregori Aminoff 1995 Prize decision/investigation :http://www.cristal.org/rietv025/foto3.jpgWho was contacted as reference ? Was Loopstra contacted and if yes, anypositive answer from him ?;-)envoyé : 18 août 2023 à 11:30de : Alan W Hewat <alan.he...@neutronoptics.com>à : Le Bail Armel <le-bail.ar...@orange.fr>cc : rietveld_l@ill.frobjet : Re: Rietveld condamnation considered as established by some more peopleBonjour Armel.No, it was van Laar who initiated it. He was annoyed that I had praised Rietveld too much in my own accounts. http://hewat.net/science/ill-hewat.html 'History of the ILL from a personal perspective'.https://journals.iucr.org/j/issues/2016/04/00/es0421/ 'Hugo Rietveld (1932–2016)'  Alan Hewat, William I. F. David and Lambert van Eijck He sent me a draft paper that he proposed to publish, but I suggested a less critical version. He agreed, and later involved Henk Schenk in producing a softer version. So it's the opposite to what you assume - Van Laar's original paper was toned down in the joint paper:https://scripts.iucr.org/cgi-bin/paper?ib5058 "The development of powder profile refinement at the Reactor Centre Netherlands at Petten" Bob van Laar and Henk SchenkWhy don't you write to van Laar and ask for a copy of his original version (abstract below)Facts about the Profile refinement method in Powder diffraction.Bob van Laar, AmsterdamJustification of the present paperThe aim of this paper is to give detailed historical insight in the procedure that led to thedevelopment of the profile refinement of neutron powder data, since then known as the'Rietveld method'. The present paper has been written by the last person still alive, involvedin the development of this method (Loopstra died in november 1998). The purpose is tocorrect some incorrectness's that have been connected to the method in course of time.Kind regards, Alan.On Fri, 18 Aug 2023 at 10:51, Le Bail Armel <le-bail.ar...@orange.fr> wrote:Bonjour Alan,My problem with the Bob van Laar and Henk Schenk paper is that it would have beencredible if signed by van Laar alone or better by Loopstra and van Laar and also ifpublished before 1980 or 1990, not in 2018.That 2018 paper looks strongly as initiated by Henk Schenk and the main argumentsinside are from old Rietveld-Schenk interferences, especially the story when Rietveld refused to plaid guilty after being accused by Schenk in a very strange manner.Now, the fact that Schenk was IUCr President may be sufficient for many people tobelieve in his version of the story. It was not sufficient for Hugo Rietveld and it is notsufficient for me.BestArmelPS - Why to insert a reference to the 1981 Pawley paper in a 1988 paper where hismethod was not used but another method much later named "Le Bail method" andbased on the Rietveld (Loopstra ??? proove it please) decomposition formula ?envoyé : 16 août 2023 à 19:08de : Alan W Hewat <alan.he...@neutronoptics.com>à : Le Bail Armel <le-bail.ar...@orange.fr>cc : "rietveld_l@ill.fr" <rietveld_l@ill.fr>objet : Re: Rietveld condamnation considered as established by some more peopleBonjour Armel. In answer to your question "Where did they find the text of the judgement ?" please see:"The development of powder profile refinement at the Reactor Centre Netherlands at Petten" Bob van Laar and Henk Schenkhttps://scripts.iucr.org/cgi-bin/paper?ib5058Van Laar worked at Petten with Rietveld, and Schenk was the IUCr president. This paper is apparently the basis of Mittemeijer's

Re: Rietveld condamnation considered as established by some more people

[Le Bail Armel]

I would be curious if the Royal Swedish Academy of Sciences has archivesconcerning this Gregori Aminoff 1995 Prize decision/investigation :http://www.cristal.org/rietv025/foto3.jpgWho was contacted as reference ? Was Loopstra contacted and if yes, any positive answer from him ?;-)envoyé : 18 août 2023 à 11:30de : Alan W Hewat à : Le Bail Armel cc : rietveld_l@ill.frobjet : Re: Rietveld condamnation considered as established by some more peopleBonjour Armel.No, it was van Laar who initiated it. He was annoyed that I had praised Rietveld too much in my own accounts. http://hewat.net/science/ill-hewat.html 'History of the ILL from a personal perspective'.https://journals.iucr.org/j/issues/2016/04/00/es0421/ 'Hugo Rietveld (1932–2016)'  Alan Hewat, William I. F. David and Lambert van Eijck He sent me a draft paper that he proposed to publish, but I suggested a less critical version. He agreed, and later involved Henk Schenk in producing a softer version. So it's the opposite to what you assume - Van Laar's original paper was toned down in the joint paper:https://scripts.iucr.org/cgi-bin/paper?ib5058 "The development of powder profile refinement at the Reactor Centre Netherlands at Petten" Bob van Laar and Henk SchenkWhy don't you write to van Laar and ask for a copy of his original version (abstract below)Facts about the Profile refinement method in Powder diffraction.Bob van Laar, AmsterdamJustification of the present paperThe aim of this paper is to give detailed historical insight in the procedure that led to thedevelopment of the profile refinement of neutron powder data, since then known as the'Rietveld method'. The present paper has been written by the last person still alive, involvedin the development of this method (Loopstra died in november 1998). The purpose is tocorrect some incorrectness's that have been connected to the method in course of time.Kind regards, Alan.On Fri, 18 Aug 2023 at 10:51, Le Bail Armel <le-bail.ar...@orange.fr> wrote:Bonjour Alan,My problem with the Bob van Laar and Henk Schenk paper is that it would have beencredible if signed by van Laar alone or better by Loopstra and van Laar and also ifpublished before 1980 or 1990, not in 2018.That 2018 paper looks strongly as initiated by Henk Schenk and the main argumentsinside are from old Rietveld-Schenk interferences, especially the story when Rietveld refused to plaid guilty after being accused by Schenk in a very strange manner.Now, the fact that Schenk was IUCr President may be sufficient for many people tobelieve in his version of the story. It was not sufficient for Hugo Rietveld and it is notsufficient for me.BestArmelPS - Why to insert a reference to the 1981 Pawley paper in a 1988 paper where hismethod was not used but another method much later named "Le Bail method" andbased on the Rietveld (Loopstra ??? proove it please) decomposition formula ?envoyé : 16 août 2023 à 19:08de : Alan W Hewat <alan.he...@neutronoptics.com>à : Le Bail Armel <le-bail.ar...@orange.fr>cc : "rietveld_l@ill.fr" <rietveld_l@ill.fr>objet : Re: Rietveld condamnation considered as established by some more peopleBonjour Armel. In answer to your question "Where did they find the text of the judgement ?" please see:"The development of powder profile refinement at the Reactor Centre Netherlands at Petten" Bob van Laar and Henk Schenkhttps://scripts.iucr.org/cgi-bin/paper?ib5058Van Laar worked at Petten with Rietveld, and Schenk was the IUCr president. This paper is apparently the basis of Mittemeijer's book. His point is that scientific discoveries are often the result of the work of many people, yet we tend to simplify the process and attribute them to individual heros. Mike Glazer is simply reviewing his book.Salutations, Alan Dr Alan Hewat, NeutronOpticsGrenoble, FRANCE (from phone)alan.he...@neutronoptics.com+33.476984168 VAT:FR79499450856http://NeutronOptics.com/hewat___   On Wed, 16 Aug 2023, 18:45 Le Bail Armel, <le-bail.ar...@orange.fr> wrote:In a book :How Science Runs – Impressions from a Scientific Career. By Eric J. MittemeijerReviewed by Mike Glazer"In another section, the author has some criticism about the famous Rietveld method in powder diffraction. He points out that the original idea for this method was put forward by Bert O. Loopstra, who later discussed the idea of whole-pattern fitting with Bob van Laar. In order to create a computer program to carry out the method, they hired the computer-savvy Hugo M. Rietveld. The first paper by Loopstra and Rietveld was published in Acta Crystallographica in 1969, having been submitted in 1968. A later paper published in 1969 by Rietveld alone in Journal of Applied Crystallography is the one that is always quoted and led to the name ‘Rietveld method’ or ‘Rietveld refinement’. Mittemeijer points out that this did grave injustice to the origi

Re: Rietveld condamnation considered as established by some more people

[Le Bail Armel]

Bonjour Alan,My problem with the Bob van Laar and Henk Schenk paper is that it would have beencredible if signed by van Laar alone or better by Loopstra and van Laar and also ifpublished before 1980 or 1990, not in 2018.That 2018 paper looks strongly as initiated by Henk Schenk and the main argumentsinside are from old Rietveld-Schenk interferences, especially the story when Rietveld refused to plaid guilty after being accused by Schenk in a very strange manner.Now, the fact that Schenk was IUCr President may be sufficient for many people tobelieve in his version of the story. It was not sufficient for Hugo Rietveld and it is notsufficient for me.BestArmelPS - Why to insert a reference to the 1981 Pawley paper in a 1988 paper where hismethod was not used but another method much later named "Le Bail method" andbased on the Rietveld (Loopstra ??? proove it please) decomposition formula ?envoyé : 16 août 2023 à 19:08de : Alan W Hewat à : Le Bail Armel cc : "rietveld_l@ill.fr" objet : Re: Rietveld condamnation considered as established by some more peopleBonjour Armel. In answer to your question "Where did they find the text of the judgement ?" please see:"The development of powder profile refinement at the Reactor Centre Netherlands at Petten" Bob van Laar and Henk Schenkhttps://scripts.iucr.org/cgi-bin/paper?ib5058Van Laar worked at Petten with Rietveld, and Schenk was the IUCr president. This paper is apparently the basis of Mittemeijer's book. His point is that scientific discoveries are often the result of the work of many people, yet we tend to simplify the process and attribute them to individual heros. Mike Glazer is simply reviewing his book.Salutations, Alan Dr Alan Hewat, NeutronOpticsGrenoble, FRANCE (from phone)alan.he...@neutronoptics.com+33.476984168 VAT:FR79499450856http://NeutronOptics.com/hewat_______   On Wed, 16 Aug 2023, 18:45 Le Bail Armel, <le-bail.ar...@orange.fr> wrote:In a book :How Science Runs – Impressions from a Scientific Career. By Eric J. MittemeijerReviewed by Mike Glazer"In another section, the author has some criticism about the famous Rietveld method in powder diffraction. He points out that the original idea for this method was put forward by Bert O. Loopstra, who later discussed the idea of whole-pattern fitting with Bob van Laar. In order to create a computer program to carry out the method, they hired the computer-savvy Hugo M. Rietveld. The first paper by Loopstra and Rietveld was published in Acta Crystallographica in 1969, having been submitted in 1968. A later paper published in 1969 by Rietveld alone in Journal of Applied Crystallography is the one that is always quoted and led to the name ‘Rietveld method’ or ‘Rietveld refinement’. Mittemeijer points out that this did grave injustice to the originator of the method, Bert Loopstra. Rietveld later left science to become a librarian: Mittemeijer says the notion that he left science because he was disappointed that the method had not found wide acceptance at the time is just a ‘fairy tale’. Thus, according to the author, the profile refinement method should more justly be called the ‘Loopstra method’, concluding that this story has a sad ending."https://www.iucr.org/news/newsletter/etc/articles?issue=156393_138339_result_page=39Where did they find the text of the judgement ? Any verdict somewhere ? Condamned by "impressions" !Any text from Loopstra who had a lot of time to tell something but never do it ?Flagged at PubPeer :https://blog.pubpeer.com/publications/79219E32306099C040C633FFABE6EChttps://blog.pubpeer.com/publications/05241C3D2890D43ED23BA1905CD32Chttps://blog.pubpeer.com/publications/9D12C10951333B68B27FB891266A88Best,Armel Le Bail++ Please do NOT attach files to the whole list  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 Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++
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Re: Rietveld condamnation considered as established by some more people

[Le Bail Armel]

>And there are other examples. See this brief review of "Whole Pattern Fitting - The Pawley Method" (1980) yet few people now attribute this kind of profile refinement to Pawley. http://pd.chem.ucl.ac.uk/pdnn/solve1/pawley.htmFew people ? At least me :https://onlinelibrary.wiley.com/iucr/itc/Ha/ch3o5v0001/sec3o5o2o2o1/?And 2168 papers cite the 1980 Pawley paper according to Google Scholar as of today.Be more clear. What are exactly those other examples ?ALB
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Rietveld condamnation considered as established by some more people

[Le Bail Armel]

In a book :How Science Runs – Impressions from a Scientific Career. By Eric J. MittemeijerReviewed by Mike Glazer"In another section, the author has some criticism about the famous Rietveld method in powder diffraction. He points out that the original idea for this method was put forward by Bert O. Loopstra, who later discussed the idea of whole-pattern fitting with Bob van Laar. In order to create a computer program to carry out the method, they hired the computer-savvy Hugo M. Rietveld. The first paper by Loopstra and Rietveld was published in Acta Crystallographica in 1969, having been submitted in 1968. A later paper published in 1969 by Rietveld alone in Journal of Applied Crystallography is the one that is always quoted and led to the name ‘Rietveld method’ or ‘Rietveld refinement’. Mittemeijer points out that this did grave injustice to the originator of the method, Bert Loopstra. Rietveld later left science to become a librarian: Mittemeijer says the notion that he left science because he was disappointed that the method had not found wide acceptance at the time is just a ‘fairy tale’. Thus, according to the author, the profile refinement method should more justly be called the ‘Loopstra method’, concluding that this story has a sad ending."https://www.iucr.org/news/newsletter/etc/articles?issue=156393_138339_result_page=39Where did they find the text of the judgement ? Any verdict somewhere ? Condamned by "impressions" !Any text from Loopstra who had a lot of time to tell something but never do it ?Flagged at PubPeer :https://blog.pubpeer.com/publications/79219E32306099C040C633FFABE6EChttps://blog.pubpeer.com/publications/05241C3D2890D43ED23BA1905CD32Chttps://blog.pubpeer.com/publications/9D12C10951333B68B27FB891266A88Best,Armel Le Bail
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Re: How to publish structure determination from powder easily ! (with the good link !!)

[Le Bail Armel]

Journals the most frequently chosen for publishing a SDPD, from the beginning up to 2007 :http://www.cristal.org/iniref/journal.html(yes, convincing the referees that this is possible is still difficult ;-)BestArmel
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Re: searching for an article

[Le Bail Armel]

https://www.iucr.org/__data/assets/pdf_file/0003/21657/CPD32.pdfenvoyé : 17 avril 2023 à 15:33de : davide.lev...@gmail.comà : rietveld_l@ill.frobjet : searching for an articleHi, I am looking for this article: Coelho, A.A. & Kern, A. (2005): Discussion of the indexing algorithms withinTOPAS. - CPD Newsletter, 32, 43-45. Is there anyone that can send me it?ThanksDavide ++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++
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Re: cif file

[Le Bail Armel]

If it is Na-P1 then :http://www.crystallography.net/cod/result.php?text1=Na-P1BestArmelenvoyé : 18 janvier 2023 à 15:45de : Susana Conconi à : rietveld_l-requ...@ill.frobjet : cif fileDear all I need the cif file ICSD 009550 with Zeolite P1 structure . The corresponding PDF file is 01-071-0962.Can anyone send it to me?Thanks in advance Susana     Prof. Maria Susana Conconi Dto. de Quimica – Facultad de Ciencias Exactas – UNLPCentro de Tecnologia de Recursos Minerales y CerámicaCETMIC (CONICET-UNLP-CIC PBA)Cno. Centenario y 506 – M.B. GonnetBuenos Aires . Argentina https://cetmic.unlp.edu.ar/https://www.exactas.unlp.edu.ar/ ++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++
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Re: refinement

[Le Bail Armel]

Nice job !Happy new year.Armelenvoyé : 6 janvier 2023 à 12:36de : Frank Girgsdies à : KULDEEP SINGH <2019phdph...@curaj.ac.in>, rietveld_l@ill.frobjet : Re: refinementDear Kuldeep,First of all, a refinement (I suppose you mean Rietveld refinement?) requires a crystal structure model, which in turn requires that you have a rather precise knowledge about the identity/composition of the crystalline phase you want to refine. XRD is not an elemental analysis method, and perovskite structures can be formed with many, many elements. Unfortunately, you forgot to mention what elements your material is composed of.I tired an identification anyway, using the latest edition of the PDF-4+ database. However, despite the fact that the pattern looks definitely perovskite-like, there was no match close enough. Trying to tune the lattice parameters of some better candidate structures revealed that something is weird about your pattern, as the positions of related reflections do not agree with each other.Then I tried to shift the pattern on a trial-and-error basis and found that it has in fact a severe zero shift of more than 0.4 degrees 2theta. It could also be a serious sample height (a.k.a. displacement) error, since these two errors are rather similar in effect. However, in order to refine a displacement correction, I would need to know your goniometer radius.I performed a Le Bail fit assuming a GdFeO3 type structure (in setting Pbnm) and obtained a reasonable fit yielding the following lattice parameters:a = 5.26617(12) Åb = 5.62135(16) Åc = 7.48743(19) Åzero error = -0.4428(8) deg. 2thetaWith this zero error information, I went back to the PDF search.Based on that, my best guess is that your sample could be Ho(Cr0.5Mn0.5)O3.Best wishes and Happy New Year,Frank GirgsdiesOn 23.12.2022 06:16, KULDEEP SINGH wrote:Hi all,please help to refine this simple data of perovskite i am stuck in it.angle 20-80step size 0.01wavelength 1.5404*Kuldeep Singh**Research Scholar**Department of PhysicsCentral University of Rajasthan**Bandarsindri-305817**District-Ajmer, Rajasthan*ᐧ++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++
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Re: "2d materials don't exist" editorial??

[Le Bail Armel]

Hi,You will find a lot of 0D, 1D, 2D "serious mistakes" there :http://cristal.org/grinsp.htmlSo, think to replace such false descriptions by the correct "0P, 1P and 2P terminology.ThanksArmelenvoyé : 24 décembre 2022 à 09:01de : Matthew Rowles à : RIETVELD_L Distribution List objet : Re: "2d materials don't exist" editorial??Hi allI think this is the onehttps://scripts.iucr.org/cgi-bin/paper?S1600576721001606 MatthewOn Fri, 23 Dec 2022, 10:00 Matthew Rowles,  wrote:This might be it, but the link is to the iucr homepage:Google: "letter to the editor" two-dimensional "layer groups" graphene iucrOn Fri, 23 Dec 2022 at 09:53, Matthew Rowles  wrote:Hi allA while ago (months, years??) I recall reading an editorial or letter to the editor about materials being referred to as "2D", and how they're actually 3D, and just periodic in the plane, and should be referred to as 2P and a relevant layer group.Does anyone recall such a thing?ThanksMatthew++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/
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Re: refinement

[Le Bail Armel]

Your pattern match well with Bixbyite (plus some impurity)http://www.crystallography.net/cod/9007522.htmlUsing FPSM http://nanoair.dii.unitn.it:8080/sfpm/BestArmelenvoyé : 15 septembre 2022 à 18:37de : KULDEEP SINGH <2019phdph...@curaj.ac.in>à : rietveld_l@ill.frobjet : refinementAnybody can provide me Rietveld refinement of the following data.angle 10-90scane step 0.01Pyrochlore compound Fe2Mn2O7Kuldeep SinghResearch ScholarDepartment of PhysicsCentral University of RajasthanBandarsindri-305817District-Ajmer, Rajasthanᐧ++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++
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Re: Datlab - Peak Fitting

[Le Bail Armel]

Hello,Ask to the author :https://www.fkf.mpg.de/person/31429/5302167BestArmelenvoyé : 6 février 2022 à 17:20de : Shrinivas Kulkarni à : "rietveld_l@ill.fr" objet : Datlab - Peak FittingHello,I am looking for a website from where I can get Datlab: K. Syassen, ‘‘Datlab, version 1.38XP,’’ MPI/FKFStuttgart, Germany.Please suggest. Thank you.Regards,Shrinivas. ++Please do NOT attach files to the whole list Send commands to  eg: HELP as the subject with no body textThe Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/++
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Re: Simultaneous refinement of multiple atoms sharing same site

[Le Bail Armel]

If more than 2 atoms sharing the same site, then fire the chemist...
Armel
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Rietveld poll provisory result

[Le Bail Armel]

Hi All

>I though this discussion would divide the community but from 
Armel’s pole (good idea) it hasn’t. 

Yes Alan (C. not H. ;-), thanks !

Rietveld poll provisory result after 2 weeks :

Yet only 54 Rietveld mailing list subscribers feeling concerned by a 
possible change of the name of their favourite method suggested
by the recent vL paper. 

The current result is :

Changing for "Loopstra method" :         2 votes
for "Profile method" :             3 votes
for "Loopstra, van Laar & Rietveld method" :  1 vote
no change (Rietveld method) :       48 votes

no opinion                  ~1500 (!)

Voting is not too late for those coming back to work in September after
a long August month of conferences.

Web link :
https://doodle.com/poll/gh3v3nfhue599w23

Best

Armel


PS - 
After the Rietveld crucifixion - some arguments for a resurrection

Changing the "Rietveld method" name would give reason to the vL paper, i.e.
admitting that H.M. Rietveld had stolen Loopstra idea and van Laar Mathematics.
Voting people in this Rietveld mailing list are obviously not convinced by the
main argument of the vL paper (grossly that any job made by a post-doc has to
be co-signed by his boss, otherwise this is robbing because acknowledgements are
not enough - a quite simplistic and brutal view). Deontology of research in 
public laboratories is well documented but not always respected. In July 1992,
the CNRS explained by a letter to his labs that "it is useless that the
laboratory director name appears on all the publications." So, imagine how were 
things by the end of the sixties. In the editorial of Head & Neck 11 (1989) 
293, 
entitled "Responsible Autorship", H. Goepfert stated "...The number of authors 
should be limited to those who truly contributed to the study - substantially 
and creatively - in originating the concept, designating a protocol, and 
supplying the scolastic fuel, academic environment, and expert technical 
supervision for the study. Routine performance or technical tasks or simple 
management responsibilities does not merit authorship but does merit 
acknowledgement. In simple terms, authors must have genuine hands-on 
involvments." It looks in this affair that Hugo Rietveld having obtained his 
PhD under the supervision of Ted Maslen (who had come from Oxford where he 
studied under Dorothy Hodgkin) and having already a paper (among others) 
published in Nature before coming to Petten - so he was no less than a well
confirmed crystallographer with computer skills - has decided to acknowledge 
Loopstra and van Laar in his main 1969 paper instead of listing them as 
co-authors. 

Half a century later, this is contested by the only survivor (van Laar) not 
claiming in 2018 that H. Schenk was wrong in writing in 2001 "Loopstra had 
the idea that it should be better to use the whole powder profile rather 
than estimated intensities to solve structures, van Laar worked it out 
mathematically and Rietveld programmed it." But does this affirmation can 
resist to some deepest analysis when Hugo Rietveld tells another story : 
"With my experience of using computers for single crystal structure 
refinements and having seen their enormous capacity for handling large 
amounts of data, I saw the spectre of increasing the number of data by a 
factor of ten by using the individual intensities y(i), instead of the 
integrated intensities, constituted no real barrier" ? Schenk accuses 
Rietveld to have modified one of his original text in his absence, 
replacing "Loopstra had the idea" by "Rietveld had the idea". And this fact 
is presented as a proof of Rietveld dishonesty. But had Rietveld any other 
choice than to correct the error in Schenk absence since he really had the 
idea and performed the mathematics ? From where Schenk (IUCr president at 
that time) had taken this incredible affirmation which he let under Hugo's 
eyes and then go away apparently without even discussing it ? Apparently
that Schenk view was from a book by C. D. Andriesse (2000) "...because he 
published alone in 1969 it came to be known as the Rietveld method and the 
contribution of his counsellors was consigned to the dustbin of history."
At least this story is more than strange and it is presented at the end of 
the vL paper as the decisive blow. Well, is this whole stuff a kind of 
revenge of Schenk over Rietveld because the latter contested his views 
about the origin of the Rietveld method - that Rietveld was no more than a 
programmer executing a command ? It is clear that if Rietveld had not 
corrected the Schenk sentence attributing the idea to Loopstra, and the 
mathematics to van Laar, then Schenk could have concluded, well, you see, 
he has agreed...

The fact is that Rietveld signed alone both of his seminal 1967 and 1969 
papers. And what happened just after that ? There are not a lot of papers 
citing Rietveld (1967) as soon as 1968 or 1969, before his 

Re: Rietveld website cancelled ?

[Le Bail Armel]

 

>For Armel, here are a couple of examples of automatic indexing, search-match 
>and structure DETERMINATION from neutron powder data.

 

OK, let us make a 2018 analysis of 
Pawley & Hewat (1985) Acta Ctyst. B41, 136-130.
according to 2002 criteria


sample : CF3Cl = strong chemical information

Neutron : D1A (ILL) lamda = 2.98 A

Indexing : Visser (1969) : orthorhombic cell

C-centered from systematic absences

estimation of 4 molecules per cell

A packing-analysis program written to investigate CF3Cl in Cmc21
two variables needed :
translation of the molecule along y and rotation in the yz plane

Unit cell refined using the ALLHKL (Pawley, 1981) program

Final full refinement by EDINP (Pawley, 1980)

All this fits well into the SDPD 2002 maze
http://www.cristal.org/CAC-XX/Hewat-maze.jpg

You had Pawley with you...
His packing-analysis software can be considered as a precursor
of what is called nowadays the direct-space approach, rotating
and translating a known molecule (using a grid-search approach
I presume in that case) till obtaining a good fit.

A pity that he has not solved his 1981 example for his Pawley method
(decafluorocyclohex-1-ene, C6F10) using that software (was a bit
more complex).

So, this 1985 SDPD paper cannot be considered as a good example for
a confirmation of the "structure determined by the Rietveld method"
approach. but sure it is a nice structure DETERMINATION from neutron

powder data.

 


Best

Armel

 

 

 

 

> Message du 29/08/18 12:33
> De : "Alan Hewat" 
> A : "Armel Le Bail" 
> Copie à : "rietveld_l@ill.fr" 
> Objet : Re: Rietveld website cancelled ?
> 
>
> A clear distinction having my complete agreement. (Armel)
Ouf. Nous sommes d'accord enfin :-) For Armel, here are a couple of examples of 
automatic indexing, search-match and structure DETERMINATION from neutron 
powder data. Very few citations though; crystallographers largely ignored 
neutron powder diffraction before 1987 and Hi-Tc :-)


__
>
   Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE 
+33.476.98.41.68
>         http://www.NeutronOptics.com/hewat
> __



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Re: Rietveld website cancelled ?

[Le Bail Armel]

 

The Hugo Rietveld crucifixion is off limits. If it is not here that we can 
discuss of it, then where ?

Contrarily to you I find a good fit with religion. And vL did not use blank 
shots.

 

Armel

 

 

 

> Message du 30/08/18 13:48
> De : "Alan Hewat" 
> A : "rietveld_l@ill.fr" 
> Copie à : 
> Objet : Re: Rietveld website cancelled ?
> 
>

> You dig !
Please stop digging Armel. Loaded guns, grave digging and religion are off 
limits.


__
>
   Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE 
+33.476.98.41.68
>         http://www.NeutronOptics.com/hewat
> __








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Re: Rietveld website cancelled ?

[Le Bail Armel]

Hi,

 

>It all depends on the definition


I know since a long time that it is risky to appear discussing on that 
list containing so many gurus of the Rietveld god (christened in 1978 
by Sabine and Young ; almost nobelized in 1995 ; crucified in 2018 by 
van Laar and Schenk). If god has said that his method could "determine" 
a structure, then all gurus must agree and defend the point.

But the world has changed a lot. Indeed, structure determination from
powder diffraction data has become possible. New gods appeared 30 years
ago. Rietveld is the central god in the process according to the SDPD 
maze :  http://www.cristal.org/CAC-XX/maze.jpg
However, when the SDPD whole process is described linearly, the Rietveld 
method place is not central, it is the ultimate thing to do.

Central or ultimate, this is enough apparently for the Rietveld gurus
to tell that there is only one god, their god. Then this strange 
"refinement=determination" law in their bible.

You dig !

Armel

PS - Anyway, I will continue to do my best for a resurrection, since I
recognize being one of his sons.

 

 

 

 

> Message du 29/08/18 19:00
> De : "Peter Y. Zavalij" 

> A : "% MailingList Rietveld" 
> Copie à : elb...@jhu.edu
> Objet : Re: Rietveld website cancelled ?
> 
>

It all depends on the definition. If/when we agree on the definition, there is 
usually no points for further arguing.
Anyway we could call Relieved method a structure determination from powder data 
as long as it does not included solving structure (or as David elegantly put - 
true structural solution).
Peter









Peter Y. Zavalij
Director - X-ray Crystallographic Center
University of Maryland, 
College Park, MD 20742
> 

>










>

>

On Wed, Aug 29, 2018 at 12:38 PM David Elbert  wrote:
>

Absolutely important that people understand that the Rietveld method is 
structure refinement and not solution, but as Larry points out sometimes you 
can get a more out of it if you’re clever… and have no other choice!   Here’s a 
second example:  

>
Stubbs et al., 2010, Uranyl phosphate sheet reconstruction during dehydration 
of metatorbernite [Cu(UO2)2(PO4)2·8H2O], American Mineralogist 95 (8-9): 
1132-1140 which is a bit of a brute-force approach to implying structures of 
some uranyl phosphates in a synchrotron heating experiment.  Joanne Stubbs 
sorted through known structures of related materials and used observed trends 
in refinements to select similar structures to further investigate.  Able to 
then postulate reasonable structures which then refined to the observed data 
and provided insight into this interesting group of materials.

>
Not the standard way to employment of Rietveld Refinement and certainly not 
true structural solutions, but a smart, useful, and rather satisfying 
application nonetheless.

>
Best-
David
>

>





David Elbert
> Hopkins Extreme Materials Institute
Malone Hall
> Johns Hopkins University
> 3400 N. Charles St
> Baltimore, MD 21218
> 
> (410) 516-5049
> 
> elb...@jhu.edu
> 
>

> 
> 
> 
> 
> 
>





>


On Aug 29, 2018, at 12:09 PM, Larry Finger  wrote:


On 08/29/2018 04:15 AM, Le Bail Armel wrote:
>
Hi,
> After the IUCr Monograph on Crystallography 13 (2002)
> entitled "Stucture Determination from Powder Diffraction Data"
> you may find in the preface :
> "Although the Rietveld method of structure refinement from powder
> diffraction data is often loosely considered to be synonymous with structure
> determination, it is not. The Rietveld method only comes into play in the
> final stage of the structure solution process when an approximate structural
> model has been found."
> WIF David, K Shankland, LB McCusker, C Baerlocher
> A clear distinction having my complete agreement.
> Armel
>

> Armel,
> 
> Although the above statement may be generally true, I can provide a counter 
> example. In Max W. Schmidt, Larry W. Finger, Ross J. Angel, and Robert E. 
> Dinnabier, "Synthesis, crystal structure, and phase relations of AlSiO2OH, a 
> high pressure hydrous phase", American Mineralogist, V. 83, 881-888, 1998, we 
> only had a powder - no single crystals. From data measured at ESRF, we used 
> GSAS to isolate the peaks of interest for the unknown phase, and used program 
> TREOR to autoindex the unknown and identify the impurity phases. We then 
> extracted intensities using the LeBail method, and determined the structure 
> using direct methods with program SIRPOW. The structure was then refined with 
> GSAS. We were even able to locate the H atom from Fourier maps!
> 
> Even 20 years ago, it was possible to determine the structure from X-ray 
> powder patterns.
> 
> Larry

RE: Rietveld website cancelled ?

[Le Bail Armel]

Hi Bob,

 

A kind of unique case isn't it ?

How many of such extreme examples can you list 18 years after it ? OK, some 
papers by Margiolaki, et al...

 

But the question was :

 

>As a long time practitioner of powder XRD (since 1972) I was there when the 
>superconductor craze hit in the mid-1980s.  At that time it was recognized the 
>Rietveld Method was useful only for REFINING structures which were generally 
>accepted from single crystal x-ray analysis.

>The http://www.cristal.org/rietv025/ link says the method "[allows] an 
>accurate determination of the structure."  I take that statement to mean no 
>model is required; Rietveld Analysis can determine structure without 
>preconceived model.

 

i.e. a good crystallographer, when reading "determination" thinks that no model 
is required. Then telling that the (Rietveld) method allows an accurate 
determination of the structure is misleading since that method only allows for 
a structure refinement.

 

So, a comment such as yours seems extremely out of the subject.

"a protein structure (a new insulin phase) was solved by rigid body Rietveld 
refinement"

This is a too short and strange way to present the thing. You indexed the 
pattern, guessed a model from what was already known about insulin, and had the 
chance it was good enough for the Rietveld refinement convergence. The 
determination did not included exclusively the Rietveld method, but also your 
mind and a lot of chance- congratulations.

 

You dig.

 

Armel

 

 

> Message du 29/08/18 18:26
> De : "Von Dreele, Robert B." 
> A : "Larry Finger" , "Le Bail Armel" , "Toby, Brian H." 
> Copie à : "Rietveld_L@ill.fr" 
> Objet : RE: Rietveld website cancelled ?
> 
> Hi Armel,
> A more extreme example was in Acta D56, 1549-1533 (2000) where a protein 
> structure (a new insulin phase) was solved by rigid body Rietveld refinement 
> from a synchrotron powder data set & subsequently confirmed by a single 
> crystal analysis (see Acta Cryst. (2001). D57, 1091-1100). NB: this kind of 
> thing has also happened more recently (see papers by Margiolaki, et al).
> Bob Von Dreele
> 
> -Original Message-
> From: rietveld_l-requ...@ill.fr  On Behalf Of Larry Finger
> Sent: Wednesday, August 29, 2018 11:10 AM
> To: Le Bail Armel ; Rietveld_L@ill.fr
> Subject: Re: Rietveld website cancelled ?
> 
> On 08/29/2018 04:15 AM, Le Bail Armel wrote:
> > Hi,
> > 
> > After the IUCr Monograph on Crystallography 13 (2002)
> > 
> > entitled "Stucture Determination from Powder Diffraction Data"
> > 
> > you may find in the preface :
> > 
> > "Although the Rietveld method of structure refinement from powder
> > 
> > diffraction data is often loosely considered to be synonymous with 
> > structure
> > 
> > determination, it is not. The Rietveld method only comes into play in 
> > the
> > 
> > final stage of the structure solution process when an approximate 
> > structural
> > 
> > model has been found."
> > 
> > WIF David, K Shankland, LB McCusker, C Baerlocher
> > 
> > A clear distinction having my complete agreement.
> > 
> > Armel
> 
> Armel,
> 
> Although the above statement may be generally true, I can provide a counter 
> example. In Max W. Schmidt, Larry W. Finger, Ross J. Angel, and Robert E. 
> Dinnabier, "Synthesis, crystal structure, and phase relations of AlSiO2OH, a 
> high pressure hydrous phase", American Mineralogist, V. 83, 881-888, 1998, we 
> only had a powder - no single crystals. From data measured at ESRF, we used 
> GSAS to isolate the peaks of interest for the unknown phase, and used program 
> TREOR to autoindex the unknown and identify the impurity phases. We then 
> extracted intensities using the LeBail method, and determined the structure 
> using direct methods with program SIRPOW. The structure was then refined with 
> GSAS. We were even able to locate the H atom from Fourier maps!
> 
> Even 20 years ago, it was possible to determine the structure from X-ray 
> powder patterns.
> 
> Larry
> 
> 
>++
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Re: Rietveld website cancelled ?

[Le Bail Armel]

OK, seems that the SDPD book preface looks unclear to some.

 

Western movies adepts well know that sentence :

"You see, in this world there's two kinds of people, my friend: those with 
loaded guns, and those who dig. You dig. .."

 

Similarly, there are two kinds of people, those believing that the sense of the 
words "structure determination" and


"structure refinement" are the same, and the others. You dig.


 

Best


 

Armel


 

 

 

 

> Message du 29/08/18 18:09
> De : "Larry Finger" 
> A : "Le Bail Armel" , Rietveld_L@ill.fr
> Copie à : 
> Objet : Re: Rietveld website cancelled ?
> 
> On 08/29/2018 04:15 AM, Le Bail Armel wrote:
> > Hi,
> > 
> > After the IUCr Monograph on Crystallography 13 (2002)
> > 
> > entitled "Stucture Determination from Powder Diffraction Data"
> > 
> > you may find in the preface :
> > 
> > "Although the Rietveld method of structure refinement from powder
> > 
> > diffraction data is often loosely considered to be synonymous with structure
> > 
> > determination, it is not. The Rietveld method only comes into play in the
> > 
> > final stage of the structure solution process when an approximate structural
> > 
> > model has been found."
> > 
> > WIF David, K Shankland, LB McCusker, C Baerlocher
> > 
> > A clear distinction having my complete agreement.
> > 
> > Armel
> 
> Armel,
> 
> Although the above statement may be generally true, I can provide a counter 
> example. In Max W. Schmidt, Larry W. Finger, Ross J. Angel, and Robert E. 
> Dinnabier, "Synthesis, crystal structure, and phase relations of AlSiO2OH, a 
> high pressure hydrous phase", American Mineralogist, V. 83, 881-888, 1998, we 
> only had a powder - no single crystals. From data measured at ESRF, we used 
> GSAS 
> to isolate the peaks of interest for the unknown phase, and used program 
> TREOR 
> to autoindex the unknown and identify the impurity phases. We then extracted 
> intensities using the LeBail method, and determined the structure using 
> direct 
> methods with program SIRPOW. The structure was then refined with GSAS. We 
> were 
> even able to locate the H atom from Fourier maps!
> 
> Even 20 years ago, it was possible to determine the structure from X-ray 
> powder 
> patterns.
> 
> Larry
> 
> 
>++
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++

Re: Rietveld website cancelled ?

[Le Bail Armel]

 

>Very few citations though;

 

The fact is that you don't cite this couple of examples in your own list of 
selected publications :

http://hewat.net/science/

If you find them of poor interest, the World follows you.

 

Armel

 

PS - A positive search-match (using the COD) signifies that the structure is 
already determined (not always if you use ICDD), then if you wish, you may 
refine it by the Rietveld method

 

 

> Message du 29/08/18 12:35
> De : "Alan Hewat" 
> A : "Armel Le Bail" 
> Copie à : "rietveld_l@ill.fr" 
> Objet : Re: Rietveld website cancelled ?
> 
>
> A clear distinction having my complete agreement. (Armel)
Ouf. Nous sommes d'accord enfin :-) For Armel, here are a couple of examples of 
automatic indexing, search-match and structure DETERMINATION from neutron 
powder data. Very few citations though; crystallographers largely ignored 
neutron powder diffraction before 1987 and Hi-Tc :-)


__
>
   Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE 
+33.476.98.41.68
>         http://www.NeutronOptics.com/hewat
> __






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RE: Rietveld website cancelled ?

[Le Bail Armel]

Hi,

 

After the IUCr Monograph on Crystallography 13 (2002)

entitled "Stucture Determination from Powder Diffraction Data"

you may find in the preface :

"Although the Rietveld method of structure refinement from powder

diffraction data is often loosely considered to be synonymous with structure

determination, it is not. The Rietveld method only comes into play in the

final stage of the structure solution process when an approximate structural

model has been found."

WIF David, K Shankland, LB McCusker, C Baerlocher

 

A clear distinction having my complete agreement.

 

Armel

http://www.cristal.org/CAC-XX/maze.jpg

http://www.cristal.org/CAC-XX/Rietveld.ppt

 

 

> Message du 29/08/18 10:14
> De : "May, Frank" 
> A : "Alan Hewat" , "rietveld_l@ill.fr" 
> Copie à : 
> Objet : RE: Rietveld website cancelled ?
> 
> To all:
> 
> Initially I sent this to Alan who suggested I open discussion to the entire 
> community. I've posted similar in past years and have been FLAMED. Please 
> keep it civil. ;-)
> =
> As a long time practitioner of powder XRD (since 1972) I was there when the 
> superconductor craze hit in the mid-1980s. At that time it was recognized the 
> Rietveld Method was useful only for REFINING structures which were generally 
> accepted from single crystal x-ray analysis.
> 
> The http://www.cristal.org/rietv025/ link says the method "[allows] an 
> accurate determination of the structure." I take that statement to mean no 
> model is required; Rietveld Analysis can determine structure without 
> preconceived model.
> 
> Thanks for reading.
> 
> Blessings from toasty and warm St. Louis, MO.
> 
> Frank May
> Research Investigator
> University of Missouri-St. Louis
> 
> formerly at Monsanto Company (which recently became part of 
> BAYER)++
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Re: Rietveld

[Le Bail Armel]

Argh ! Shame on us three !

 

But be careful to not confuse an example with a counter-example ;-)

 

In 1986 had already started the times where Rietveld was so famous that giving 
his name in the paper was sufficient. You can probably find >20.000 such papers 
citing the Rietveld method and not his 1967 or 1969 papers. Rietveld's real 
number of citations is probably closer to >40.000 than to 15.000. But you know 
that already...

 

Best,

 

Armel

 

 

 

 

> Message du 22/08/18 14:23
> De : "Alan Hewat" 
> A : "rietveld_l@ill.fr" 
> Copie à : 
> Objet : Re: Rietveld
> 
>

> Another example.. Loopstra, van Laar and Breed Physics Letters 26A(11) 1968, 
> 526 (AleB)

>
Examples are easy. In Gibaud, Le Bail and Bulou J. Phys. C: Solid State Phys. 
19 (1986) 4623
"...the Rietveld program modified by Le Bail (1985)" is used to refine data 
collected at ILL on D1A (Hewat & Bailey 1976) without citing either Rietveld or 
the people who built the diffractometer, helped with the data collection, and 
supplied the 1972 Rietveld code. 

__
>
   Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE 
+33.476.98.41.68
>         http://www.NeutronOptics.com/hewat
> __





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Re: Rietveld

[Le Bail Armel]

The >1500 subscribers can vote... :

 

https://doodle.com/poll/gh3v3nfhue599w23

 

Best,

 

Armel

 

 

 

> Message du 21/08/18 19:10
> De : "Alan Hewat" 
> A : "rietveld_l@ill.fr" 
> Copie à : 
> Objet : Re: Rietveld
> 
>
> As a matter of course we didn't took part in the discussion... (Schenk)
> ...people pretending now to speak in place of Loopstra should stop to do so 
> (Le Bail)
What a contrast of style and substance. Late believers are true believers, and 
Passion evicts Doubt.
>

> 
Seeking sanity, I refer back to Miguel and the meaning of truth and knowledge.:
>
> Scientists cannot ask anyone for the absolute truth  (A consideration valid 
>for one but also for two) 
> By absolute truth I meant universal or divine truth. We can certainly ask 
> everyone for the complete truth as they perceive it - opinion, the first kind 
> of knowledge according to the Dutch philosopher, and "the only source of 
> falsity" :-) Scientists try to approach the second kind of knowledge 
> (reason). The third kind is divine truth, and even Armel cannot ask for that.


>

On Tue, 21 Aug 2018 at 17:44, Le Bail Armel  wrote:
>

> Dear Rietvelders,

>  

> The last sentence of the van Laar & Schenk paper is  :
> 
> "It seems to us justified to replace the name ‘Rietveld method’ 
> in the future by the working title of the past: ‘profile method,’ 
> or to honour the inventor by using ‘Loopstra method’."
> 
> So, shame on Rietveld for having stolen Loopstra idea and mathematics
> from van Laar. Shame also for having modified a paper from Henk Schenk
> telling early the "true."
> 
> Thanks to Bob van Laar for being so obviously modest and not 
> considering that his mathematics matter in the method.
> 
> Hope that among the 700 readers there are a few like me finding
> that paper completely incoherent and not convincing at all.
> 
> The fact is that Hugo Rietveld was convinced that he was the
> main conceiver of the method and it is absolutely not impossible
> that Loopstra was only one of the numerous guys who had the idea
> tor fit a complete powder pattern instead of extracted intensities.
> Rietveld himself could be one of such guys. He decided to thank

> Loopstra and van Laar "for their suggestions and helpful criticisms".

> And this supposes that Loopsta and van Laar have very probably

> read the paper before submission and seen clearly that Rietveld

> was the only author of that now most cited 1969 paper...
> 
> One of the main surprising sentence in the paper is :
> "If the community had awarded this (Loopstra & Rietveld, 1969) 
> paper the recognition it deserved, the described profile refinement 
> method would probably not be named after Rietveld alone. From the 
> point of view of historical correctness this would have been much 
> closer to the truth."
> 
> Indeed, in that 1969 paper one can find :
> "In neutron powder diffraction, it is customary to use as 
> least-squares data the integrated values of the diffraction peaks, 
> even when these consist of more than one Bragg reflexion. The loss 
> of information inherent in this technique can, however, be eliminated 
> by using the complete observed powder pattern in a direct manner 
> (Rietveld, 1967). This method determines the esti-mates of the 
> structure parameters by finding a least-squares fit between the 
> observed and calculated profile intensities."
> 
> So, Loopstra cosigns a paper in 1969 with Rietveld in which he
> recognizes using the Rietveld method as described in the Rietveld
> 1967 paper !
> 
> Later Loopstra published many papers referencing the Rietveld 
> 1969 paper.
> 
> My conclusion is that people pretending now to speak in place
> of Loopstra should stop to do so.
> 
> Best,
> 
> Armel Le Bail
> 
> 
>

> Message du 21/08/18 16:01
> > De : h.sch...@uva.nl
> > A : Rietveld_l@ill.fr
> > Copie à : 
> > Objet : [SUSPECTED SPAM] Rietveld
> > 
> >We were worried that our article was not reaching the powder 
> >crystallographers as it was published, although Open Access, in Acta Cryst 
> >A. Jim Kaduk advised me to use this excellent list-server, so I became 
> >member and posted our message. Now I�m happy to mention that since that day 
> >Acta A counted almost 700 downloads for the paper, so we clearly reached our 
> >goal.
> > 
> > I was also pleased to follow the discussion, very lively and interesting, 
> > and thank all contributors. The discussion was led day and night by our 
> > excellent chair/moderator, Alan Hewat. 
> > Alan, you did a fantastic job, summarising, ad

Re: Rietveld

[Le Bail Armel]

Dear Rietvelders,

 

The last sentence of the van Laar & Schenk paper is  :

"It seems to us justified to replace the name ‘Rietveld method’ 
in the future by the working title of the past: ‘profile method,’ 
or to honour the inventor by using ‘Loopstra method’."

So, shame on Rietveld for having stolen Loopstra idea and mathematics
from van Laar. Shame also for having modified a paper from Henk Schenk
telling early the "true."

Thanks to Bob van Laar for being so obviously modest and not 
considering that his mathematics matter in the method.

Hope that among the 700 readers there are a few like me finding
that paper completely incoherent and not convincing at all.

The fact is that Hugo Rietveld was convinced that he was the
main conceiver of the method and it is absolutely not impossible
that Loopstra was only one of the numerous guys who had the idea
tor fit a complete powder pattern instead of extracted intensities.
Rietveld himself could be one of such guys. He decided to thank

Loopstra and van Laar "for their suggestions and helpful criticisms".

And this supposes that Loopsta and van Laar have very probably

read the paper before submission and seen clearly that Rietveld

was the only author of that now most cited 1969 paper...

One of the main surprising sentence in the paper is :
"If the community had awarded this (Loopstra & Rietveld, 1969) 
paper the recognition it deserved, the described profile refinement 
method would probably not be named after Rietveld alone. From the 
point of view of historical correctness this would have been much 
closer to the truth."

Indeed, in that 1969 paper one can find :
"In neutron powder diffraction, it is customary to use as 
least-squares data the integrated values of the diffraction peaks, 
even when these consist of more than one Bragg reflexion. The loss 
of information inherent in this technique can, however, be eliminated 
by using the complete observed powder pattern in a direct manner 
(Rietveld, 1967). This method determines the esti-mates of the 
structure parameters by finding a least-squares fit between the 
observed and calculated profile intensities."

So, Loopstra cosigns a paper in 1969 with Rietveld in which he
recognizes using the Rietveld method as described in the Rietveld
1967 paper !

Later Loopstra published many papers referencing the Rietveld 
1969 paper.

My conclusion is that people pretending now to speak in place
of Loopstra should stop to do so.

Best,

Armel Le Bail




> Message du 21/08/18 16:01
> De : h.sch...@uva.nl
> A : Rietveld_l@ill.fr
> Copie à : 
> Objet : [SUSPECTED SPAM] Rietveld
> 
>We were worried that our article was not reaching the powder crystallographers 
>as it was published, although Open Access, in Acta Cryst A. Jim Kaduk advised 
>me to use this excellent list-server, so I became member and posted our 
>message. Now I�m happy to mention that since that day Acta A counted almost 
>700 downloads for the paper, so we clearly reached our goal.
> 
> I was also pleased to follow the discussion, very lively and interesting, and 
> thank all contributors. The discussion was led day and night by our excellent 
> chair/moderator, Alan Hewat. 
> Alan, you did a fantastic job, summarising, adding information and making 
> essential links. Thank you very very much!
> 
> As a matter of course we didn�t took part in the discussion, but now I like 
> to make one comment on the question �why now�. This is a quite long story and 
> carries a lot of non-scientific information. So it couldn�t be part of our 
> paper, but may be once it will be written down and published in the IUCr 
> Newsletter.
> 
> Henk Schenk


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Re: Rietveld

[Le Bail Armel]

 

>"...the method did not suddenly appear in a flash of inspiration of a single 
>person, but was the result of the work of three individuals... Loopstra, van 
>Laar and Rietveld.".

 

And more precisely :

 

" HS wrote in Dutch:

‘Loopstra had the idea that it should be better to use the whole powder profile 
rather than estimated intensities to solve structures, van Laar worked it out 
mathematically and Rietveld programmed it."

 

I conclude then :

no idea for Rietveld and van Laar since they are from Loopstra;

no mathematics for Rietveld and Loopstra;

no programming for Loopstra and van Laar.

 

A very clear result of the work of three individuals. The HS view...

 

Seems that Rietveld had not the same opinion and claimed for ideas too and 
possibly for mathematics as well.

 

Best,

 

Armel

 

 

 
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Re: Rietveld

[Le Bail Armel]

Hi,

 

Reading again the Acta Cryst. (2018). A74, 88–92 paper :

 

"So, summarized here, HS wrote in Dutch:

‘Loopstra had the idea that it should be better to use the whole powder profile 
rather than estimated intensities to solve structures, van Laar worked it out 
mathematically and Rietveld programmed it. Nowadays it is known as the Rietveld 
method’. HS submitted the raw manuscript without figures and photographs. At the 
time he was President of the IUCr, very busy and travelling a lot. So when he 
saw the article again, it was already printed, there were four illustrations 
provided by Rietveld himself, and slight changes had been made to the text, 
which in essence had changed its meaning. In the sentence above Loopstra was 
replaced by Rietveld and it now started with ‘Rietveld had the idea that...’. 
Also a last sentence about Rietveld’s hobby, as a jazz pianist, had been added."

 

This is the "coup de grace"...

 

But could Hugo Rietveld admit to be transformed in a simple programmer by  
‘Loopstra had the idea that it should be better to use the whole powder profile 
rather than estimated intensities to solve structures, van Laar worked it out 
mathematically and Rietveld programmed it' ?

 

Seriously, HS really think that Hugo Rietveld had absolutely no idea, and then 
worked out mathematically nothing ?

 

This was a complete provocation to give to Hugo Rietveld access to such an 
insulting text against him before its publication.

 

I just prefer to believe that Hugo Rietveld restored the truth by inserting 
‘Rietveld had the idea that...’. instead of Loopstra.

 

There is no proof of the contrary given by Loopstra himself, defined as a man 
"who apparently pushed hard" by Alan. He had a lot of time to push hard in 
order to contradict the legend and has done nothing apart using the method and 
citing quietly the 1969 paper from Hugo Rietveld.

 

Best,

 

Armel

 

 

 

 

 

 

> Message du 18/08/18 12:24
> De : "Alan Hewat" 
> A : le-bail.ar...@orange.fr
> Copie à : "rietveld_l@ill.fr" 
> Objet : Re: Rietveld
> 
>
> As I get older, I believe less and less in legends  (AH)
> 
> ...the aristocracy of powder diffractionists is displaced (AleB)

>
I don't believe in aristocracy either :-) After Bill David, Lambert van Eijck 
and I published Hugo Rietveld's glowing obituary, I received a rough draft of 
the vL paper, and was frankly shocked. But after finding that others shared 
those views, I suggested a re-write of the paper to make it (perhaps) less 
controversial and more historical, supported where possible with evidence from 
the literature. Still, the paper seemed to address questions I myself had about 
the legend.

>
1) How could a young man, educated as a classical crystallographer (Bragg 
peaks, structure factors, Fourier transforms...) produce the revolutionary idea 
of simply refining the structure to fit the observed profile ? None of the 
professional crystallographers I knew accepted that idea - only physicists and 
chemists who used crystallography as a tool. It was a naive physicist's 
approach.

>
2) How could Rietveld (1967) in his first paper not emphasise this 
revolutionary departure from classical crystallographic techniques ? It was 
almost as if he didn't consider that refining  magnetic moments and atom 
displacements was real crystallography, just a refinement problem where 
compromises had to be made to get a required result with an inadequate computer.

>
3) Why did Rietveld leave science in 1974 if he thought that he had achieved 
something remarkable ? He had a permanent job at a well funded laboratory and a 
technique that would eventually revolutionise powder diffraction. Ordinary 
people like me couldn't even get a job at Cambridge (thanks Mike :-) and had to 
live with a succession of 3 year contracts in foreign countries.

>
When I first knew Hugo, he was a modest, unassuming man, unlike Loopstra who 
apparently pushed hard. When he saw that "The response was slight, or, rather, 
non-existent" perhaps like other crystallographers for 20 years he himself 
doubted the value of profile refinement.

>
And no I don't think the crystallographic establishment should get to name it. 
Everyone knows what "profile refinement" means.


>

On Sat, 18 Aug 2018 at 11:29, Le Bail Armel  wrote:
>

> Hi,

>  

> >As I get older, I believe less and less in legends. In the IUCr 1999 issue 
> >that I cited, I should have also mentioned that there is an interesting 
> >article on p.4 called "The Powder Diffraction Handicap" by Armel le Bail :-)

>  

> Indeed, "never say never" is verified again. The powder diffraction handicap 
> (overlapping) can be considered as suppressed by XFEL

> https://www.xfel.eu/ where each single microcrystal of the powder produces 3D 
> diffraction dat

Re: Rietveld

[Le Bail Armel]

Hi,

 

>As I get older, I believe less and less in legends. In the IUCr 1999 issue 
>that I cited, I should have also mentioned that there is an interesting 
>article on p.4 called "The Powder Diffraction Handicap" by Armel le Bail :-)

 

Indeed, "never say never" is verified again. The powder diffraction handicap 
(overlapping) can be considered as suppressed by XFEL

https://www.xfel.eu/ where each single microcrystal of the powder produces 3D 
diffraction data, and all data are recombined !

But for solving too simple problems, you will not have access to that 
overloaded machine and will have to continue to use your laboratory powder 
diffractometer and (now) classical approaches. 

 

So, once again, the aristocracy of powder diffractionists is displaced, this 
time from third generation synchrotron to XFEL, amusing, new legends will be 
built, probably.

 

Best,

 

Armel

 
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Re: Rietveld

[Le Bail Armel]

 

>Probably, that's how legends begin.

 

Your presence on so many pictures together with Hugo Rietveld, suggests that 
your responsibility in establishing and approving the legend is quite high, 
between 30 and 60% maybe, but I recognize that Rwp is poorly satisfying for 
this fit.

http://home.wxs.nl/~rietv025/crystallografen-s.jpg

 

Then times to destroy the legend come, and you want to be a part of it too, 
apparently.

 

Should we rename the Rietveld decomposition formula (equation 7 in his 1969 
paper) the Loopstra decomposition formula ? I am lost.

 

Best,

 

Armel
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none

[Le Bail Armel]

Identité Message:[EMAIL PROTECTED]
X-Sender: [EMAIL PROTECTED](Non vérifié)
X-Mailer: QUALCOMM Windows Eudora Pro Version 4.0.1 
Date: Tue, 09 Nov 1999 07:26:32 +0100
To: RIETVELD_L Distribution List [EMAIL PROTECTED]
From: Armel Le Bail [EMAIL PROTECTED]
Subject: Re: Advice on a new diffractometer
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

My question is, what would be a good choice for a second diffractometer in
this situation (ie what brand, what kind of monochromators and detectors,
etc)?  

Try "NIST" as keyword in PowBase, you will obtain 2 patterns which
are the best you can do in a laboratory, and a link to a discussion
on that question and to more demonstration patterns.

Armel Le Bail
http://sdpd.univ-lemans.fr/powbase/