Re: Rietveld

[David Elbert]

I am an interested reader of this thread, but have no direct knowledge of any 
of the history.  I will add, however, a small point about Alan’s last note 
suggesting we could go back to calling the process “Profile Refinement” and 
dodge the personal attribution. 

My point is that naming things after people may over simplify attribution, but 
it also does a larger service by emphasizing that science is a process done by 
people.  Science is not, as some uninitiated believe, simply a cold statement 
or revelation of facts.  People *do* science while simultaneously *guiding* or 
even inventing the science.  They define what become interesting problems while 
human curiosity and interests provide the driving force in the direction of 
scientific work. 

Naming things is an important part of how humans think about things and 
associating ideas or techniques with a scientist or group is an accurate way of 
representing how the process of science works. It is a human process and I’d 
rather not expunge that even though the attribution can rarely capture the full 
scope of the history.

That’s my two-cents as we say here in the US.

-David


David Elbert
Hopkins Extreme Materials Institute
Malone Hall
Johns Hopkins University
3400 N. Charles St
Baltimore, MD 21218

(410) 516-5049

elbert_at_jhu.edu






> On Aug 17, 2018, at 5:30 AM, Alan Hewat  wrote:
> 
> >  ...your responsibility in establishing and approving the legend is quite 
> > high
> >  Then times to destroy the legend come, and you want to be a part of it 
> > too, apparently.
> 
> 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 :-)
> 
> I personally think we should use Rietveld's original term "Profile 
> Refinement", which I already used in my Harwell report 
> 1973_The_Rietveld_Program_for_the_Profile_Refinement_of_ 
> Neutron_Diffraction_Powder_Patterns_AERE_R7350-von_Dreele_annotations.pdf 
> 
>   
> 
> On Fri, 17 Aug 2018 at 10:31, Le Bail Armel  > wrote:
>  
> >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
> 
> ++
> Please do NOT attach files to the whole list 
> Send commands to 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/ 
> 
> ++
> 
> 
> 
> -- 
> __
>Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE 
>  +33.476.98.41.68
> http://www.NeutronOptics.com/hewat 
> 
> __
> ++
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> ++
> 

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RE: Rietveld

[Radovan Cerny]

« Profile refinement » is misleading as with Rietveld method we are refining 
also the crystal structure …

I think that it is too late to change the terminology in the text books. The 
history of science is full of wrong legends. One point of view of the people 
involved in the story is now published in the article, and as Hugo Rietveld 
cannot answer the questions, there is no sense to correct the terminology. 
Maybe, our respective bodies CPD-IUCr and EPDIComm may give a recommendation?

Radovan Cerny
Laboratoire de Cristallographie, DQMP
Université de Genève
24, quai Ernest-Ansermet
CH-1211 Geneva 4, Switzerland
Phone  : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08
mailto : radovan.ce...@unige.ch
URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm

De : rietveld_l-requ...@ill.fr  De la part de Alan 
Hewat
Envoyé : vendredi 17 août 2018 11:31
À : rietveld_l@ill.fr
Objet : Re: Rietveld

>  ...your responsibility in establishing and approving the legend is quite high
>  Then times to destroy the legend come, and you want to be a part of it too, 
> apparently.

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 :-)

I personally think we should use Rietveld's original term "Profile Refinement", 
which I already used in my Harwell report 
1973_The_Rietveld_Program_for_the_Profile_Refinement_of_ 
Neutron_Diffraction_Powder_Patterns_AERE_R7350-von_Dreele_annotations.pdf

On Fri, 17 Aug 2018 at 10:31, Le Bail Armel 
mailto:le-bail.ar...@orange.fr>> wrote:



>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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--
__
   Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
mailto:alan.he...@neutronoptics.com>> 
+33.476.98.41.68
http://www.NeutronOptics.com/hewat
__
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Rietveld

[Mike Glazer]

Perhaps I could make a small contribution to this discussion (I hope Alan will 
not mind too much). In the early 1970's I had my research group at the 
Cavendish Lab in Cambridge and I advertised for a postdoc to come and work on 
physical properties and structure of ferroelectric crystals (or something like 
that: my memory may not be precise). Alan at that time was working in Harwell 
and he applied for the job. I asked him to come and see me to discuss this and 
this was when I learnt about Rietveld.  One should remember that prior to 
Rietveld (and Pawley) powder diffraction was a subject mainly used for 
identification of materials and had little general research impact. Anyway, I 
decided not to offer him the job, partly because I had another candidate who 
was experienced in physical property measurements of ferroelectrics, but also 
because I felt that it was in Alan's own interest to continue to concentrate on 
his Rietveld work. I think by this I did him a service!(true Alan?). 

Anyway for a few years afterwards we collaborated on some Rietveld refinements, 
initially at Harwell and later at the ILL. Alan had taken Rietveld's original 
code and added some more coding to do anisotropic displacement parameters, and 
I think that our refinements of some perovskite structures included refinement 
of ADP's, which turned out to look reasonably meaningful. They seem to have 
stood the test of time.

Going from memory, Alan it seems to me was the first person to latch onto the 
significance of Rietveld's program and was responsible for making it widely 
known. He deserves a lot of credit for this.

My only other direct involvement in Rietveld (apart from just using it) was 
when I began working on synchrotron radiation. We collected powder data using a 
solid state energy dispersive detector. Despite its low resolution I was 
interested to see if we could apply the Rietveld process to the data. I had a 
young postdoc working with me and I asked him to have a go at writing some 
software to do this. It turned out that he was an awful programmer and it took 
a lot of time to get something working. In the end we succeeded (just!) and 
were able to get reasonable structural parameters from the data.

Mike Glazer

PLEASE NOTE : I SEND ALL FUTURE EMAILS TO ME AT   mike.gla...@physics.ox.ac.uk

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Re: Rietveld

[Alan Hewat]

>  ...your responsibility in establishing and approving the legend is quite
high
>  Then times to destroy the legend come, and you want to be a part of it
too, apparently.

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 :-)

I personally think we should use Rietveld's original term "Profile
Refinement", which I already used in my Harwell report
1973_The_Rietveld_Program_for_the_Profile_Refinement_of_
Neutron_Diffraction_Powder_Patterns_AERE_R7350-von_Dreele_annotations.pdf



On Fri, 17 Aug 2018 at 10:31, Le Bail Armel  wrote:

>
>
> >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
> ++
> 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/
> ++
>
>

-- 
__
*   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]

 

>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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Re: Rietveld

[Alan Hewat]

Armel's supervisor, Daniel Louer, made important contributions to the
description of the line shape for profile refinement with x-rays, but that
was 10 years later. His 1986 paper
 references Rietveld (1969) but
uses a different type of profile refinement developed by Sonneveld & Visser
(1975). "*The strategy consists of the refinement of different peaks in a
cluster, one at a time..."*

Daniel was eventually won over to the Petten method, and there is a nice
picture of him with Hugo at the 1999 IUCr Glasgow symposium that I
organised on "30 Years of Rietveld Refinement
" (page 7).

At my age, I prefer Googling the literature rather than relying on my
remembrances :-)

On Fri, 17 Aug 2018 at 00:22, Alan Hewat 
wrote:

> > * I remember that a Fortran version was in tests there (in Rennes in
> 1975-76), probably one of these 27 copies distributed by Hugo Rietveld
> himself to institutes all over the world.*
>
> Rietveld worked with neutron powder diffraction on magnetic and heavy
> metal oxides. An x-ray lab. in Rennes was probably not one of the selected
> 27 institutes all over the world. As Rietveld wrote in the paper you cited,
> "*The response was slight, or, rather, non-existent*", and by 1975-76 he
> had already left science. Probably, that's how legends begin.
>
> On Thu, 16 Aug 2018 at 21:05, Le Bail Armel 
> wrote:
>
>> Hi,
>>
>>
>>
>> Sorry for that blank email...
>>
>> Since times are to old stories about the Rietveld method, I first
>> heard about it in 1975-76 during my "3ème cycle" thesis in D. Grandjean
>> laboratory, Rennes, France, under the direction of D. Louër. The thesis
>> was about profile-shapes broadening due to powder small grain size.
>> http://www.cristal.org/rapport/Le-Bail-These-3eme-Cycle.pdf
>>
>> I did not use the Rietveld method at that time but I remember that
>> a Fortran version was in tests there, probably one of these 27 copies
>> distributed by Hugo Rietveld himself to institutes all over the world.
>> http://home.wxs.nl/~rietv025/Rietveld%20Method.docx
>>
>> My profile shapes were quite Lorentzian and there was considerable
>> anisotropic broadening, something not yet accountable by the Rietveld
>> method at that time focused on Gaussian peak shapes.
>>
>> I was not back about the Rietveld method before the XIII IUCr Congress,
>> 1984, Hamburg, where I proposed a way to undertake such X-ray complex
>> shapes: "The Rietveld method using an experimental profile convoluted
>> by adjustable analytical function". This was the ARIT software later
>> used in 1987 for intensities extraction purposes by iterating the
>> Rietveld decomposition formula, leading to many SDPDs (Structure
>> Determination by Powder Diffractometry).
>> http://cristal.org/mespapiers-PDF/1984/1984-Rietveld-a31186.pdf
>> http://www.cristal.org/arit.html
>>
>> Best,
>>
>>
>>
>> Armel
>>
>>
>>
>> PS- Better to write your own story clearly yourself before to leave the
>> planet,
>>
>> even if nobody apparently read it.
>>
>> http://www.cristal.org/iniref/lbm-story/
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> ++
>> 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/
>> ++
>>
>>
>
> --
> __
> *   Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE *
>  +33.476.98.41.68
> http://www.NeutronOptics.com/hewat
> __
>


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