You might like to add it to COD :-)
Sure.
Let me a few days to add the 50 crystal structures lacking in the
Crystallography Open Database. There is some opposition in the world
to attain this target and not a lot of help from the crystallographers
themselves (one should ask why :-().
Hi,
Well, after 30 years in a X-ray lab, I conclude that both technicians and
PhDs find more convenient to use a phone rather than a screwdriver for
calling the manufacturer in case of serious dysfunctionment...
Best,
Armel
++
All deviations from expected values (1.514 and 1.634) are within 3 e.s.u.s
that are around 0.03 A in average.
About absurdity, there are different sensibilities...
With such a definition above, 1.72(3) instead of 1.634 is just OK for
Leonid. Where would he see a limit before applying
that
restraints may be admitted, and even constraints for H atoms.
Not sure that your young students have received a complete formation if
they have to argue Even Armel Le Bail has to apply restraints!. Well,
yes, even not ashamed.
Best,
Armel
All deviations from expected values (1.514 and 1.634) are within 3 e.s.u.s
that are around 0.03 A in average. Further improvements seem possible, but
it will require more time and efforts.
So, one more example of underestimated information capacity of powder data
and overestimated necessity
The problem of having jammed the wrong molecule
into a unit cell can be identified by restraints which
are violated. With rigid bodies it is more difficult to
find out what the data are trying to tell you. Is this
wrong molecule issue the problem you fear?
I prefer resolving such problems
http://danse.cacr.caltech.edu/polls/results.php?sid=22httphttp://danse.cacr.caltech.edu/polls/results.php?sid=22://danse.cacr.caltech.edu/polls/results.php?sid=22
This Caltech survey is a bit strange.
The Caltech experts range indexing programs in the
category 'structure solution', mixed
I tend to think that FULLPROF is the clear favorite of the magnetic
scattering community, but I have no data to prove that.
Interesting enough is the variation of the number of
citations of this paper :
RODRIGUEZCARVAJAL J
RECENT ADVANCES IN MAGNETIC-STRUCTURE DETERMINATION BY
NEUTRON POWDER
Please tell me the name of any good book you have come across...
List of books (and much more) there :
http://sdpd.univ-lemans.fr/DU-SDPD/semaine-1/sdpd-1.html
including :
Fundamentals of Powder Diffraction and Structural
Characterization of Materials
Vitalij K. Pecharsky, Peter Y.
Hello,
For those asking for atomic coordinates at this mailing list.
If you have difficulties in accessing the crystallography
databases (CSD, ICSD, CRYSTMET, ICDD), you may consider
to give your opinion by signing the petition in favour
of opening the access to crystal data on the Web.
Visit
I am pleased to inform you that an academic version of DDM is available
now at reduced price. This version is very elaborate, sophisticated and
difficult to use. It is specially designed for smart, wise and highly
experienced academicians. The current academic price is 1 Russian
rubles, but
P.S. The word deposit has additional meanings equivalent to
sediment, sludge, settlings, dreg, varnish etc.
Thanks. Just what I was meaning. The association sludge varnish
is even more accurate ? Sediment is fine because the Academy
has a strong effect of attraction and capture many excited
does anyone knows the atomic positions for
PDF No. 33-1229 alpha-Na2Ca4(PO4)2SiO4Space-group P-3m1
or where I can find it?
I coudn't find in the ICSD database 2/2004.
Producing a calculated powder pattern from 33-1229
and using a search/match software suggests that this
compound is highly
what kind of search/match software do you use?
The best in the world... : EVA (Socabim/Bruker)
See the Search Match Round Robin 2002:
http://sdpd.univ-lemans.fr/smrr/
http://sdpd.univ-lemans.fr/smrr/results/
published :
Results and conclusions of the internet based
Search/Match Round Robin 2002,
To my knowledge in GSAS it's not possible to perform the
structural refinement of the same phase with two kinds of
profile model functions, one for sharp peaks and the other
for broadened peaks (I already saw that the function n.4 by
Stephens doesn't match my case).
It is possible with Fullprof.
CAC2 = 2nd Algerian Congress of Crystallography,
17-21 April 2005: http://cac2.lacmom-dz.com/
Constantine - Algeria
The list of such freeware really available is short :
FOX, PSSP, ESPOIR.
Only FOX allows for your optional feature 4.
Many links at the SDPD Internet Course sessions 7 and 8 :
http://sdpd.univ-lemans.fr/DU-SDPD/semaine-7/sdpd-7.html
It is also true that no development has been done for anisotropy. Not yet!
Well, if all previous works about trying to take account of size/strain
anisotropy in the Rietveld method are nothing yet, this allows to
close the discussion. Let us wait for really serious developments to
come.
Armel
The diffraction alone can not decide. Significantly different physical
size distributions could describe equally well the peak profile
(J.Appl.Cryst. v35 (2002) 338-346 - self citation too).
Nicolae Popa
Looking at your figures 6b1 and 6b2, I measure how we
differ on the sense of significantly
Why dissident Armel ?
I am an adept of the open access to the knowledge,
your religion looks different.
Armel
from http://www.dictionary.com:
Disagreeing, as in opinion or belief.
\Dissi*dent\, a. [L. dissidens, -entis, p. pr. of dissidere to sit apart,
to disagree; dis- + sedere to sit: cf. F.
I have no other choice but to use ICSD if I pretend to be
an expert/wizard (=adept ??) in inorganic chemistry.
Armel, that is the nicest compliment I have ever heard about ICSD.
Sincerely, Thanks ! Alan xxx
See how we are different.
For you this is a compliment.
For me no other choice is an
What we see in diffraction is the column lengths (volume area
averaged) and the classics were not full ignoring the shape and radius
(radii) distribution(s).
Nicolae Popa (Mister, Messieur, Don, Dom, etc.)
Of course I agree with you that completely different shapes
may correspond to the same
Small error, sorry,
three of the possible arrangement were :
|--|
| |--|
| | |--|--|
|--|--|--|--|
|--|
| | |--|
| |--|--| |
|--|--|--|--|
|--|
| | |--|
| | | | |--| |--|
|--| |--|
Seriously Thanks guys I did not know about this site till I retired and
have wished I knew a lot earlier.
Try also the dissident SDPD Mailing List :
http://groups.yahoo.com/group/sdpd/
(though Sir Kenneth is also a subscriber...).
Armel
I will be grateful to all if there is a discussion on the term Domain Size
over this list.
Domain size is an incomplete definition.
Line broadening due to size effect is related to the definition
of coherent diffracting domains. The coherency comes
from the fact that the three-dimensional
Hi,
Few days back I have put a question on the list but has not yet replied me.
I desperatly need your help.
The fact is that your question has a complex answer...
I have evaluated the instrumental parameters U,V,W from cagliotti relation
and 'a' and 'b' from the eta relation.
Can anybody tell me
Not much money for Science in Colombia ?
The ultra basic mathematics in the Rietveld method
are available for free at the author himself Web
site : http://home.wxs.nl/~rietv025/
In paperback, the book The Rietveld Method can be
obtained for less than 10-40 euros :
My question is: Since I am already using the constraints, therefore
somewhat imposing my solution on the structure, can I add more
complexity to the refinement, using the results of ab initio calculations,
and say that this is real?
As you probably know already, too much is too much...
Too
Hi,
Is there somewhere any cemetery of died Siemens D500 powder
diffractometers where to grab for some pieces in order to try to
repair a very old one (1982) ?-).
Armel
And he is modest as well :-)
I have to be modest. According to the CNRS, I am a
second-class researcher...
Armel
Adding 2 cents to the discussion...
But I will try to convince myself otherwise :-)
Another reason which may preclude your self-convincing is the
fact that all the very good PDF studies of materials that are not perfectly
crystallized (producing diffuse scattering), though not being amorphous,
are
I suspect that the broadening may be caused by stacking
faults or twinning, but how do I determine whether this is the case?
There is no software in which you enter the powder data and from which
the case of faulting is suggested...
Many cases of faulting in simple metals or mixed-metallic
PCOD and COD updates (a lunar Apache/PHP/MySQL application ;-) :
Total in PCOD : 714 predicted structures
Total in COD : 13967 entries
172 new entries in PCOD : hypothetical hexagonal zeolites
http://www.crystallography.net/pcod/
Selected pictures of these new entries at :
Even Armel and I have to pay to eat...
And a brain works better if the stomach is not empty...
So, this story may have convinced you that people
working on proteins are lucky with that open PDB
database, that people working on nucleic acids are
lucky with that open NDB database, that people
Hi,
My initial subject line was :
Where we go with monopolistic licensed databases ?
A bad example below...
It was changed automatically by the ILL mail server,
replacing it by the subject of the forwarded email about Endeavour.
So, if some results obtained from these monopolistic
databases are
Would anyone please send me the wykoff positions of Hopeite,
Zn3(PO4)2. [H2O]4.
Hopeite, as a mineral, can be found in the AMCSD :
http://www.geo.arizona.edu/AMS/amcsd.php
or in the COD : http://www.crystallography.net/
Both open databases.
Armel
Your operating model... is a stellar example of how one might integrate
with MySQL while still adhering to confines of the GPL or in other words,
managing to keep your product open source.
Thanks for the confirmation.
Exactly what I said : advertisement for extremely good
commercial products.
A bad example below...
Armel
==
From: Crystal Impact [EMAIL PROTECTED]
To: Crystal Impact Customers [EMAIL PROTECTED]
Date: Tue, 6 Jul 2004 11:11:01 +0200
Dear customers,
in our previous e-mail (dated June 26, 2004) we announced the next Endeavour
How to pick up the right solution between these high M20 solutions?
No exact solution to that problem related to the needle to
be found in a hay bundle.
The ultimate proof that a solution is the right one is to solve
the structure. Having only 31 hkls, this is not completely impossible
with an
In this case it is case it is expected that there
will be formation of dislocation loops in the material due to
irradiation.
Well, simulations which would be made on the same
material in the case of different kinds of dislocations
and defaults could say if really the line-broadening is
the
your reply about preferred orientation probabaly not being a problem with
a cubic mineral is of interest to me.
I can testify to have seen huge preferred orientation occuring
in some cubic perovskites, at least. Too much intensity in those
h00.
Armel
Can anybody tell me what do the terms area weighted domain size
and volume weighted domain size physically mean.
How to understand these two concepts of domain sizes physically.
Bertaut and Warren considered columns of cells along a given
hkl direction and defined a P(M) distribution
He could ask the master how is the nature so perfect.
Or could conclude by himself that powders are not single
crystals, so that symmetry may lead to systematic overlap
and irrecoverable loss of information.
Yes, anisotropic line broadening is rarely observed
with cubic compounds unless in very
(in the sense accepted for publication
twenty years ago ;-).
Best wishes with HNbO3,
Armel Le Bail
Presume one of your students makes a fit on a sample having only size
anisotropy and he is able to determine the six parameters of the ellipsoid.
But after that he has a funny idea to repeat the fit changing (hkl) into
equivalents (h'k'l'). He has a chance to obtain once again a good fit, with
Hi,
The coefficients Lij in the formula you wrote have no significance.
Our whole science is a so bad approximation to the Universe...
For the representation of an isotropic size effect , you may imagine
the mean size being the same in all directions, obtaining a
sphere. The same for a mean
Armel, do you agree with the IUCr recommendation in the
letter you cited that rich countries and individuals like you
and me should pay a little more for databases and journals
so that developing countries might pay less ? I do.
I do not. This is not little more.
Even in rich countries,
IUCr have done a great job in putting ALL Acta papers on-line.
They have also declined your proposal that they contribute
data to COD and recommend that people support existing
databases instead. So how about helping raise money from
the French equivalent of NSF for that purpose ?
There is not
Sorry if I recall what has been discussed before, but I cannot find
it in the archives. I don't use apparantly the proper search terms.
Try this in the old archive (90 emails !) :
http://sdpd.univ-lemans.fr/cgi-bin/searchrietveld.pl?Range=AllFormat=StandardTerms=bail+gsas
or this in the new
Armel will be pleased to know that the PHP-MySQL server software is
available as open source (but copyright) code from
http://icsd.ill.fr/icsd/install/
Not enough Alan, I want not only the butter but also the
money for the butter. The complete stuff fully open.
500 more CIFs in COD that week,
Hi,
The Siena School webpage states:
The aim of the school is to have the crystallographic computing experts
of the present, help train and inspire a new generation of experts in
crystallographic computing.
I am of the past, not sure of being an expert even about past things,
not sure of
What happens in the future? When Bob Von Dreele and Brian Toby, to name
two, join Al Larson in retirement, (and Al finally stops working) what
happens then?
My structure prediction software has not yet any subroutine
able to give an answer. But I believe a lot in the Open Access
current. In
The Ninth International Workshop of Crystallography
organized by the Egyptian Society of Crystallography
and its Applications (ESCA), entitled :
Recent Advances in X-Ray Powder Diffraction
is planned 27 November - 2 December 2004,
Assiut, Egypt
See the first announcement
Hi,
Have you had any response to your query? I also need to translate a CIF
file to hkl, d space and intensities. Thank you.
No answer corresponding to a complete program doing directly
the job.
I received advice to use XTAL :
http://xtal.sourceforge.net/
or/and CIFTBX :
Hi,
Searching for an open source FORTRAN program translating
series of CIF files into a seies of lists of hkl, d spacings and
intensities.
Thanks,
Armel
?
Thanks a lot,
Armel Le Bail
http://www.cristal.org/course/
Has anyone available any pcr file appropriate for this process?
See the pbb.pcr file in the list of examples delivered with the latest
Fullprof :
pbb : multi-pattern input file, mixing X-rays and neutrons : pbso4.dat
data for a combined refinement
by anonymous FTP :
charybde.saclay.cea.fr/pub/divers/fullp/ms-dos/
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
the adding of calculated powder patterns from ICSD into
the ICDD has clarified the situation for 4 entries...
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
probably much larger. If you have some names, please
send them to me.
Best wishes,
Armel Le bail
http://sdpd.univ-lemans.fr/course/
of connections at :
http://sdpd.univ-lemans.fr/museum/museum.txt
Is this useful ? Who knows ?
Best
Armel Le Bail
Only exception is Bob von Dreele, who kindly posted the GSAS
source for the benefit of Armel :-)
Unfortunately, no benefit at all until now. Still no permission for
putting it in the source code museum. Bob possibly considers
that his code is not old enough and may post an obsolete version
an idea about the phenomenon...
Armel Le Bail
http://www.cristal.org/
I am using fullproof for refine the powder data, only refine the cell
parameters, then I would like to use hkl file to expo programe, how I will
give that hkl file to expo. Plese tell me the format.
According to the Fullprof manual :
JLKH=-2
-- Output for
Well, although the specimen was nearly strain-free, strictly speaking this
was still a size-strain round robin; all the participants extracted (or
refined) strain parameters, didn't they :-)
Before to start, the Round Robin participants were said :
"Although the first sample selected for the
of the software. But that new version is still bugged...
Same problem on your machine ??
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
alified these Rietveld-derived
methods as giving dubious results, in their opinion.
Best,
Armel Le Bail
SSRR local results at : http://sdpd.univ-lemans.fr/microstruct/ssrr/
Hello Bob,
Attached is the new Linux version (with fixes).
Ooops.
Now that the GSAS Fortran source is in the mailboxes
of 300 subscribers of the Rietveld mailing list as well
as in the list archives, may I add it in the Crystallography
Source Code Museum ?-).
Armel
Knowing what the
structure does or doesn't do around the transition would be a prerequisite
to a deeper understanding of the phenomena.
We still wait for a deeper understanding of the phenomena,
since 1986, right ? And this, after thousands of characterizations.
You really think that MgB2 will
If you know how to guarantee high citation levels, go to it :-)
Alan, you already occupy the place of leader of the
Group of Crystallography at ILL, the best neutron
reactor for research in the world ;-). Knowing how
cannot ensure to succeed... There are a few other
parameters to refine.
Armel
Is it really
worth trying to belittle what should turn out to be excellent science?
A serendipity case. Once more. Where is excellency exactlly,
according to you ? I repeat that excellency would be to produce
a theory which would have allowed to predict the MgB2
superconductor properties.
Dang... I'm glad that we didn't have to wait for excellent science to
theoretically predict penicillin for us.
Absolutely ! The whole humanity is lucky that things to be
found, whatever, are discovered times to times. Fire, the wheel,
who remember the inventors ?
But our era is lacking of
Hello,
The SDPD Database includes now a list of
some powder diffraction highly cited papers,
as proposed in the ISI Web of Science (Science
Citation Index) :
http://sdpd.univ-lemans.fr/iniref/most-cited.html
Best regards,
Armel Le Bail
Paolo,
What criterion was adopted in the search? The following famous paper,
clearly of structural subject, is not on your list, but has 768 citations:
The search was on two words : "powder" AND "diffraction", occuring
either in the title or in the abstract, or in the keywords, or somewhere.
The search was on two words : "powder" AND "diffraction", occuring
either in the title or in the abstract, or in the keywords, or somewhere.
Seems a pretty restrictive criterion, and likely to favour papers on technique rather
than science (though I note that Rietveld's paper's do not qualify
I must recognize half a lie.
ISI has a strategy of conquest of the french market
about the Web of Science. They offer 2 months free
and illimited access (starting a few days ago). For
supporting this strategy, ISI has designed the 301
french laureates according to citation criteria :
, as a rule.
Oldest archives (1994-1998) are still available at :
http://sdpd.univ-lemans.fr/forum/rietveld_l/index.html
Armel Le Bail
I am working with samples that contain an unknown amorphous phase, which I would
like to quantify.
Can you obtain that "unknown amorphous phase" pure ?
What do you mean by unknown, the chemical composition
is also unknown, or do you just lack for a sructure model ?
Armel Le
the coordinates of, say, 100 atoms. Even scanning and using
an OCR program is tedious.
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
re dark stories soon ;-).
(Note that I could say about 20 known organic and
organometallic structures still lacking in ICDD PDF-2, but
they are promised for a near future).
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
data formats
are available somewhere ? What are the formats used
in the Jade+ software for a search/match with the PDF-2
database ? Thanks.
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
Refining on Crystallite size and strain in XFIT as part of
fundamental parameters fitting is important.
No preliminary results to show from XFIT applied to the
Size/Strain Round Robin CeO2 sample ?
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
ble but not yet in the habits, clearly, because almost
nobody gives opinion about the preprints.
There is a long way to a "GeneralPubFree" site.
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
However, if you carefully read some of his recent papers, you may
find the answer there (the paper on CeO2 by his group was published in Chem.
Mater.; I don't have it handy but can find out the exact citation if
needed).
I hope this was not exactly the same sample because a Round Robin
is
, have you the right
to send them on this mailing list ?
Clarifying these questions would be pertinent.
Best,
Armel Le Bail
http://www.cristal.org/
PS - I do not remember to have sent any ICSD, CSD or ICDD
entry on any crystallography mailing list. But I certainly do
remember having
of the increasing number of users. But this is not
sure, because I am confident in the ICDD efficiency in not
realizing profit at constant database cost in spite of increasing
samples sold : they just have to increase their own expenses.
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
at any time all the (current) year.
http://sdpd.univ-lemans.fr/course/
Armel Le Bail
hink that this is another good idea.
I would be interested in knowing your opinion about the "fundamental
parameters" approach, which describes profiles by analytical
profiles (generally convolutions of squared Lorentzians plus
some artifacts for creating asymmetry), anyway.
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
lities, is at :
http://sdpd.univ-lemans.fr/sdpd/espoir/oldsrc.zip
ESPOIR is distributed under the GNU General Public
Licence.
http://sdpd.univ-lemans.fr/sdpd/espoir/license.html
Best wishes,
Marc Mileur - [EMAIL PROTECTED]
Armel Le Bail - [EMAIL PROTECTED]
Armel Le Bail - Universite du Ma
at
http://www.xhuber.com
Thanks for the very nice data from the Huber camera 670.
Best,
Armel Le Bail
http://www.cristal.org/
for 1/2 century :-(((.
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
PS - Each time I send an email to the Rietveld list I get an error mail :
Subject: Unknown recipient
[EMAIL PROTECTED]
That is funny. End of that list ?-).
configurations :
http://sdpd.univ-lemans.fr/powdif/low_fwhm_and_rp.html
A. Clearfield is Rigaku-fan, seems to me, or perhaps I am
wrong :-?
Best,
Armel Le Bail
http://www.cristal.org/
with that idea of giving reference patterns. Yes,
that is curious, you just can't find such essential data...
Best,
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
powder diffractometers have problems...
if not the reactor itself. Such is life.
Armel Le Bail
http://sdpd.univ-lemans.fr/course/
That muscovite-oriented single crystal pattern is available in PowBase :
http://sdpd.univ-lemans.fr/powbase/ ,
pattern 77. It probably shows also big tube tails and maybe (?)
Kalpha3.
Best,
Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen
I'm looking forward for many discussions!
I have some naive questions :
I would like to hear exactly what is on my powder pattern:
- Kalpha3
- tube tails
or both ??
Do these effects would occur at the same angular value ?
Armel
PS - You may download that CeO2 pattern showing
gh the fit seems to have improved,
at first glance.
Has someone a powder pattern available which shows clearly
Kalpha3, and which he was able to fit by a Rietveld code
(which one ?) and obtained some improvement in the Rp
and Rwp values ?
Best,
Armel Le Bail - Universite du Maine, Laboratoire des
programs.
What is proposed exactly in BGMN ?
Best,
Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans Cedex 9, France
http://www.cristal.org/
, 1.500.000 US$ may suffice for reconstituting
the PDF-2, CSD, ICSD, CRYSTMET, all of them,
in China, or in India, maybe.
What do you think ?:-).
Best,
Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans Cedex 9, France
http
have been interested
in finding the full raw powder pattern in PDF-3 or PowBase, just
for trying to solve it, you see my point ?;-).
Best,
Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans Cedex 9, France
http://www.cristal.org/
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