diffraction software survey

[Pavol Juhas]

Dear colleagues,

enclosed is your feedback to the Rietveld-list survey on powder
diffraction software usage/preferences, which was conducted Nov 2003.

Your replies were very helpful, as we are working on a detailed scope of
diffraction software to be developed under the proposed DANSE project.
We have received 31 email replies to the survey, but we would like to
reach a wider community.  In order to do that, we have recreated this
survey online at

http://danse.cacr.caltech.edu/polls/survey.php?sid=22

We would really appreciate if you could fill out this survey and help us
determine the software needs of the diffraction community.  Those of you
who have already submitted email replies don't need to do that; we will
re-enter your replies for you.

Thanks,

Simon J.L. Billinge,
Pavol Juhas

PS: If you want to learn more about the DANSE project, please visit
http://wiki.cacr.caltech.edu/danse/index.php/Main_Page




Results of Rietveld email-list survey from 2003-11-11 conducted on
software preferences and usage of the powder diffraction community.



COUNTRY:



UK  7/31  (23%)
USA 6/31  (19%)
France  6/31  (19%)
Germany 4/31  (13%)
Italy   2/31   (6%)
Switzerland 1/31   (3%)
Portugal1/31   (3%)
Norway  1/31   (3%)
India   1/31   (3%)
Canada  1/31   (3%)
Austria 1/31   (3%)



AFFILIATION TYPE



Academia   21/31  (68%)
National lab9/31  (29%)
Other institution   2/31   (6%)
Industry1/31   (3%)



TYPE OF POWDER DIFFRACTION INSTRUMENTS USED



In-house x-ray 28/31  (90%)
Synchrotron x-ray  22/31  (71%)
Reactor neutrons   14/31  (45%)
Spallation neutrons14/31  (45%)



POWDER DIFFRACTION SOFTWARE USED FOR



---
Rietveld refinement:   31/31 (100%)
---
GSAS   28/31  (90%)
FullProf   11/31  (35%)
TOPAS   4/31  (13%)
FullProf/WinPlotr   2/31   (6%)
Rietica 2/31   (6%)
CCSL codes  1/31   (3%)
DBWS94111/31   (3%)
Materials Studio1/31   (3%)
MAUD1/31   (3%)
MPRODD  1/31   (3%)
Rietan  1/31   (3%)
WinCSD  1/31   (3%)
WinMProf1/31   (3%)

---
Peak indexing/unit cell determination: 29/31  (94%)
---
Crysfire   14/29  (48%)
Dicvol  7/29  (24%)
TREOR   6/29  (21%)
ITO 3/29  (10%)
Stoe WinXPow2/29   (7%)
UFIT2/29   (7%)
WinPlotr2/29   (7%)
CheckCell 

3 Position at ISIS in the area of Crystallography

[Radaelli, PG (Paolo)]

 
Employment Opportunities at ISIS
ISIS is in a period of major expansion, including the construction of a
second target station, with an initial phase of 7 new instruments to be
operational in 2008. 

We are looking for world-class scientists, instrument developers and
electrical engineers who can make major contributions to our current and
future research programmes.

Senior Scientists (2 positions) 
Scientists (8 positions) 
Electrical Engineers (9 positions) 
PA to the Director (1 position) 
Complete details and application forms can be found at the 
central CCLRC Job Vacancy Pages http://www.cclrc.ac.uk/Activity/Jobs





VN2624: Senior Scientist (Diffraction)
Type   Full-time 
Department/Centre   ISIS Department 
Location   RAL 
Office   RAL 

All application forms must be returned by 6 December 2004.

 Description

We are looking for a scientist with a proven research record to play a
leadership role in the development of diffraction techniques at ISIS, both
in terms of instrumentation and applications. The post will involve line
management, project management and budget management responsibilities. The
jobholder should be able to lead a team to achieve both short term and long
term goals. The successful candidate should demonstrate a broad experience
and outlook and an innovative approach.




VN2622: Instrument Scientist, Crystallography Group
Type   Full-time, 2 Posts 
Department/Centre   ISIS Department 
Location   RAL 
Office   RAL 

All application forms must be returned by 6 December 2004.

 Description

We are looking for two highly motivated and independent scientists, who will
assume responsibility for a world-leading scientific, instrument design and
instrument-operation programme within the ISIS crystallography group. The
jobholders will be required to provide an appropriate level of support for
the ISIS User Programme and will be strongly encouraged to build
collaborations with UK and foreign visiting scientists.

Applicants should have a PhD or equivalent qualification in a relevant
science or engineering discipline. The successful candidates will have a
proven track record in an area of neutron or x-ray crystallography
including, but not limited to, single-crystal neutron diffraction,
high-pressure research, magnetic neutron diffraction and cultural heritage
research. The ability to carry out independent research and an innovative
outlook towards instruments and technique development will be counted as
strong assets. Experience in the use of central facilities and the proven
ability to develop instrumentation and/or data analysis software would also
be an advantage.

  

Re: rietveld refinement

[Leonid Solovyov]

Let me put a more particular question on the size estimation from
Rietveld refinement.
If we refined the size-broadening parameters P and X of the
Thompson-Cox-Hastings function (as they are defined in J. Appl. Cryst.
(2004) 911) and corrected them for the instrumental contribution, then
can we say something about the coherent domain size DISTRIBUTION
assuming the domains approximately spherical?

Leonid Solovyov




__ 
Do you Yahoo!? 
Meet the all-new My Yahoo! - Try it today! 
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RE: rietveld refinement

[Armel Le Bail]

I'd have to disagree on this point - troublemaker I suppose!  I've 
followed the work by Langford and Louer closely, and have successfully 
applied their techniques
I do not understand on what point exactly you disagree.
The cited paper about size effect in nickel hydroxyde
is co-authored by D. Louer, and may still seem kosher to him ;-).
The full reference is :
A. Le Bail and D. Louër. J. Appl. Cryst. (1978). 11, 50-55
[doi:10.1107/S0021889878012662]
Title: Smoothing and validity of crystallite-size distributions from X-ray 
line-profile analysis
Abstract: A smoothing procedure is described which eliminates spurious 
details on crystallite-size distribution functions deduced from X-ray line 
profiles. It is based on a least-squares process with a stabilization 
scheme and is applied to composite specimens prepared by mixing known 
quantities of samples of nickel hydroxide, whose crystallite 
size-distribution functions were previously determined. Calculated and 
observed distributions and average sizes are compared. The results are 
reasonably good and show the self-consistency of the method.

Best regards,
Armel

RE: rietveld refinement

[Whitfield, Pamela]

Title: RE: rietveld refinement





 


>There was a strong size anisotropy. The X-ray study cannot
>gives the shape (you see that I agree with you on that point),
>an electron microscopy study showed that the coherently
>diffracting domains are plate-like crystallites aggregated along
>the c axis.


I'd have to disagree on this point - troublemaker I suppose!  I've followed the work by Langford and Louer closely, and have successfully applied their techniques to analyse anisotropic broadening to non-spherical (admittedly not very complex shapes - rods and octahedra) nanomaterials.  Doesn't help with a size distribution, as it only works well for a relatively monodisperse material - but it does work under some circumstances.

Pam

Re: Unexpected honour

[Armel Le Bail]

An alternative, a diversification, does not mean automatically a 
disidence. Let
us not blurred a word very dear to people like me, rising and living most of
the life in a dictatorial regime.
Nowadays, the dissidence against communism is less
distributed in the world.
The new dissidence is against a too strict capitalism, even
able to make money with public data.
Armel

Re: rietveld refinement

[Armel Le Bail]

Small error, sorry,
three of the possible arrangement were :
   |--|
   |  |--|
   |  |  |--|--|
   |--|--|--|--|
   |--|
   |  | |--|
   |  |--|--|  |
   |--|--|--|--|
   |--|
   |  | |--|
   |  | |  | |--|  |--|
   |--| |--| |--|  |--|
Armel

JOB: Instrument scientist for the high resolution powder

[Dimitri Argyriou]

Hahn Meitner Institute, Berlin
Department of Magnetism
Scientist Ph.D.
(Physicist, Chemist)
No. SF 2004/16

 
The Hahn-Meitner-Institut invites applications for a postdoctoral position
in the area of neutron powder diffraction. The successful candidate will be
the responsible scientist for the high resolution powder diffractometer, E9,
at the Berlin Neutron Scattering Center (BENSC). The Hahn-Meitner-Institut
is a German National Laboratory and a member of the Hermann von Helmholtz
Association of National Research Centres and has about 850 employees. It
hosts the Berlin Neutron Scattering Center (BENSC) (http://www.hmi.de/bensc/
 ), a user facility open to scientists from all
over the world. To probe the structure and dynamics of solids and liquids,
BENSC provides the national and international research community with
state-of-the-art neutron scattering equipment and expertise.

The successful candidate will develop neutron scattering instrumentation and
techniques, and will support BENSC users on the E9 high resolution powder
diffractometer. He/she is also expected to participate in an existing
research program on strongly correlated transition metal oxides.

 

A broad knowledge in condensed matter physics will be required as well as
experience in neutron scattering instrument development and operation. A
background in neutron diffraction, the Rietveld method, crystallography and
a strong scientific interest in transition metal oxide physics will be
strongly preferred. The successful candidate will have access and is
expected to utilize for his/her own research excellent sample preparation
facilities that include oxide powder synthesis labs (with high temperature
variable atmosphere furnaces), and a floating zone optical mirror furnace
for single crystal growth. Standard sample characterization facilities are
also available (XRD, SQUID, specific heat). Staff at BENSC have access to
25% of the beam time on all neutron scattering instruments for their own
research.

The appointment is for 3 years and is renewable for another 2 years. The
salary is in the range of 36.000 ­ 40.000 EUR per annum depending on age.
Applicants should send a letter of application, a detailed CV, a list of
publications, and copies of degrees to Hahn-Meitner-Institut Berlin, Abt.
Personal und Soziales, Glienicker Str. 100, D-14109 Berlin, Germany before
12 December 2004 quoting reference No. SF 2004/16.
 

For informal inquiries, please contact Dr. D. Argyriou (phone
+49-30-8062-3016, email [EMAIL PROTECTED]  ) or Dr.
H.A. Graf (phone +49-30-8062-2778, e-mail [EMAIL PROTECTED]).

 

 

Re: rietveld refinement

[Armel Le Bail]

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 distribution of column length.
For diffraction, and considering one direction, the columns of
cells look exactly as if they were separated. So, obviously :
   |--|
   |  |--|
   |  |  |--|--|
   |--|--|--|--|
gives the same column length distribution as :
   |--|
   |  | |--|
   |  |--|--|  |
   |--|--|--|--|
or as separated columns :
   |--| [--|
   |  | |  |
   |  | |  | |--|  |--|
   |--| |--| |--|  |--|
or etc, taking the columns in the bottum-up sense.
But, with these 3 different models (and more are possible), you
would not have the same distribution of column lengths in the
orthogonal direction...
My problem with most recent papers about size effect is that
they always consider cubic compounds, possibly spherical
crystallites etc. In such a case, all directions are gathered in
one.
Could you study something more complex sometimes ?
In my self-citation work, the study was made on nickel
hydroxyde, with hexagonal structure, looking for columns
exclusively in the direction of the c axis, using the Bertaut
formulations, with careful extraction of the column lenght
distribution after deconvolution from the instrumental effect.
There was a strong size anisotropy. The X-ray study cannot
gives the shape (you see that I agree with you on that point),
an electron microscopy study showed that the coherently
diffracting domains are plate-like crystallites aggregated along
the c axis.
So I cannot let say that "Significantly different "physical"
size distributions could describe equally well the peak profile".
This is confusing. You may say that : significantly different
crystallite shapes could describe equally well the peak profile
in cubic symmetry. I am not sure that this sentence is
valuable equally for other symmetries when looking at all
profiles. You would have maybe to restrain to the consideration
in one direction : if no change is produced in all other directions,
what is the degree of freedom for the crystallite shape now ?
Is it possible to organize the columns differently in one
direction without changing also the peak profiles in all other
directions for a triclinic compound ?
So, let us have more fun with a size strain round robin on some
complex sample  (or even a size-only round robin not on a
cubic compound ;-).
Best
Armel

Re: Unexpected honour

[Nicolae Popa]

- 

>>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.
>\Dis"si*dent\, a. [L. dissidens, -entis, p. pr. of dissidere to sit apart,
>to disagree; dis- + sedere to sit: cf. F. dissident. See
>Sit.] No agreeing;
>dissenting; discordant; different
>Our life and manners be dissident from theirs. --Robynson (More's Utopia).

>\Dis"si*dent\, n. (Eccl.) One who disagrees or dissents; one who separates
>from the established religion.

>The dissident, habituated and taught to think of his dissidenc? as a
>laudable and necessary opposition to ecclesiastical usurpation. --I.
Taylor.


Sorry, but I think there is here a mal interpretation (is correct that in
English?) of the dictionary. I don't think that the people in SDPD list are
thinking the powder diffraction differently than the people in the Rietveld
list. Or, if there are differences on some particular subject from one
member to other, this can happen also inside the same chat list. An
alternative, a diversification, does not mean automatically a disidence. Let
us not blurred a word very dear to people like me, rising and living most of
the life in a dictatorial regime.

Yours,
Nicolae Popa

RE: Unexpected honour

[Alan Hewat]

>For me "no other choice" is an intolerable constraint.

"The very existence of others may be seen as an intolerable constraint on the 
freedom of the individual."
 From "Liberty, Equality, Fraternity" by Jean-Marie Cardinal Lustiger writing 
on liberty and license.

Just as I thought, it is a question of religion. I can't argue with that. Alan.


Alan Hewat, ILL Grenoble, FRANCE  <[EMAIL PROTECTED]> fax (33) 4.76.20.76.48
(33) 4.76.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/AlanHewat.htm 
___

Re: rietveld refinement

[Nicolae Popa]

>
> >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 different". As you comment
> in the text, "The curves 1 and 2 differ in the position of the
> maximum by only 2 A and in height of the maximum by
> 9.76%".
>
> I would not call that "significantly different" but "very similar".
>
> Armel

Yes, but the figure 6b represents the COLUMN LENGTH distribution not the
CRYSTALLITE RADIUS distribution (in this case of spherical crystallites).
The crystallite radius distributions are given in 6a1 and 6a2 (lognormal and
gamma, respectively) and they are significantly different, what can be seen
also in the table 1: the average radius and the dispersions are completely
different. Nevertheless the profile of the diffraction peak is equaly well
described. And the column length distribution is quite the same (as
discussed in text and as you observed). But when we are speaking about the
"physical model" we understand in fact the distribution of the crystallite
radius (if spherical). Is that lognormal or gamma? Is the average radius
90(6) or 69(1) Angstroms, is the parameter c (determining the dispersion)
0.18 or 0.39?  We can not say only from diffraction that one is more
"physical" than other. On the other hand is the column length distribution a
full "physical" description of the crystallites, I mean of the shape and
radius (radii) distribution? I think not. You can imagine, for example, that
the crystallites are even not spherical, but ellipsoidal. It is easy to
understand that if the Euler angles representing the orientations of the
ellipsoidal principal axes with respect to the crystal axes are UNIFORMLY
distributed in their domains of definition, will be NO anisotropy effect.
Then we can think the crystallite are spherical with a certain distribution
of radius, when in fact they are ellipsoidal with other distributions of
(three) radii. But the column length distribution (and the peak profile) is
the same. 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.)

RE: Unexpected honour

[Armel Le Bail]

>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 intolerable constraint.
No thanks ! Armel

RE: Unexpected honour

[Alan Hewat]

>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


Alan Hewat, ILL Grenoble, FRANCE  <[EMAIL PROTECTED]> fax (33) 4.76.20.76.48
(33) 4.76.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/AlanHewat.htm 
___

RE: Unexpected honour

[Armel Le Bail]

I am happy to see that you are still a member of the
Rietveld list and still use ICSD,
I have no other choice but to use ICSD if I pretend to be
an expert/wizard (=adept ??) in inorganic chemistry. The
only word defining ICSD is : monopoly. The definitions
below are explicite and adequate, so that being happy
that I still use ICSD has not any sense.
Armel
PS - Definitions for "monopoly" from different sources :
   * Exclusive control by one group of the means of producing or selling a 
commodity or service: Monopoly frequently... arises from government support 
or from collusive agreements among individuals(Milton Friedman).
   * Law. A right granted by a government giving exclusive control over a 
specified commercial activity to a single party.
   * A company or group having exclusive control over a commercial 
activity.
   * A commodity or service so controlled.
   * Exclusive possession or control: arrogantly claims to have a 
monopoly on the truth.
   * Something that is exclusively possessed or controlled: showed 
that scientific achievement is not a male monopoly. A business that is the 
sole supplier of a particular good or service. Regulated monopolies, such 
as electric utilities, are generally restricted as to the returns they are 
permitted to earn. Other monopolies such as firms with unique products or 
services derived from patents, copyrights, or geographic location may be 
able to earn very high returns.
   1 : exclusive control of a particular market that is marked by the 
power to control prices and exclude competition and that esp. is developed 
willfully rather than as the result of superior products or skill

   1. The exclusive power, or privilege of selling a commodity; the 
exclusive power, right, or privilege of dealing in some article, or of 
trading in some market; sole command of the traffic in anything, however 
obtained; as, the proprietor of a patented article is given a monopoly of 
its sale for a limited time; chartered trading companies have sometimes had 
a monopoly of trade with remote regions; a combination of traders may get a 
monopoly of a particular product.

   Raleigh held a monopoly of cards, Essex a monopoly of sweet wines. 
--Macaulay.

   2. Exclusive possession; as, a monopoly of land.
   If I had a monopoly out, they would have part on 't. --Shak.
   3. The commodity or other material thing to which the monopoly relates; 
as, tobacco is a monopoly in France. [Colloq.]

   n 1: (economics) a market in which there are many buyers but only one 
seller; "a monopoly on silver"; "when you have a monopoly you can ask any 
price you like" 2: exclusive control or possession of something; "They have 
no monopoly on intelligence" 3: a board game in which players try to gain a 
monopoly on real estate as pieces advance around the board according to the 
throw of a die

RE: Unexpected honour

[Alan Hewat]

>I am an adept of the open access to the knowledge, your religion looks 
>different.

Ahh, so it is a question of Religion. (I should have known :-) Clearly a common 
title like "Sir" will not do. How about "Reverend", "Pontiff", "Grand 
Ayatollah"...

Adept:  [n]  someone who is dazzlingly skilled in any field
Synonyms: ace, expert, genius, hotshot... virtuoso, wizard


Alan Hewat, ILL Grenoble, FRANCE  <[EMAIL PROTECTED]> fax (33) 4.76.20.76.48
(33) 4.76.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/AlanHewat.htm 
___

RE: Unexpected honour

[Armel Le Bail]

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.
\Dis"si*dent\, a. [L. dissidens, -entis, p. pr. of dissidere to sit apart, 
to disagree; dis- + sedere to sit: cf. F. dissident. See 
Sit.] No agreeing; 
dissenting; discordant; different
Our life and manners be dissident from theirs. --Robynson (More's Utopia).

\Dis"si*dent\, n. (Eccl.) One who disagrees or dissents; one who separates 
from the established religion.

The dissident, habituated and taught to think of his dissidenc? as a 
laudable and necessary opposition to ecclesiastical usurpation. --I. Taylor.

adj 1: characterized by departure from accepted beliefs or standards [syn: 
heretical, 
heterodox] 2: 
disagreeing, especially with a majority [syn: 
dissentient, 
dissenting(a)] 
n : a person who dissents from some established policy [syn: 
dissenter, 
protester, 
objector, 
contestant]

Source: 
WordNet ® 2.0, © 2003 Princeton University

Re: rietveld refinement

[Armel Le Bail]

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 different". As you comment
in the text, "The curves 1 and 2 differ in the position of the
maximum by only 2 A and in height of the maximum by
9.76%".
I would not call that "significantly different" but "very similar".
Armel

Bond angle and bond length

[Krushna]

  
Hi,
I am using FULLPROF program code for Rietveld refinement of XRD data.
I don't know how to obtain values of bond angles and bond lengths by refinements, or some reliable freeware available to calculate. Please suggest.

Krushna

RE: Unexpected honour

[Alan Hewat]

>>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 :

Why "dissident" Armel ? I am happy to see that you are still a member of the 
Rietveld list and still use ICSD, but if your are trying for an English title, 
using these to construct "dissident" alternatives doesn't seem quite "cricket" 
:-) 

Especially in reply to a very welcome compliment to the Rietveld list. Thanks 
Laurie.

Alan.

Alan Hewat, ILL Grenoble, FRANCE  <[EMAIL PROTECTED]> fax (33) 4.76.20.76.48
(33) 4.76.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/AlanHewat.htm 
___

Re: rietveld refinement

[Nicolae Popa]

> methodology, if not that they are "physical" (I believe they are
> "physical" in case of size-only effect).

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