Whitfield, Pamela wrote:
I've come across a unit cell that seems to give alot of software a
headache when generating the powder patterns. I've tested 6 software
packages with this (including commercial) and found only a 50% success
rate in generating a good pattern with correct relative intensi
Jacco
I didn't actually use these cif files for my simulations, I entered the data
by hand (including fractions where the software would take it). :-)
The cif data is just there for other people's convenience - different powder
software like different cif file formats anyhow. In any case, if th
Whitfield, Pamela wrote:
The problem also occurred in a program that would take fractional
coordinates, so that's not the only snag.
I suggested another one:
From: Jacco van de Streek
- The matrices representing the space-group operators are no longer
diagonal, and the distinction between R*h and
> - The matrices representing the space-group operators are no longer
> diagonal, and the distinction between R*h and h*R (where R is the
> rotation matrix and h is the reciprocal space vector [h,k,l]) becomes
> important when calculating systematic absences.
This does make sense. Many of the pro
> The cell is in space group P3112
> There aren't even any structures with this space group in the ICSD
> (not even the other enantiomorph P3212)
Hmm, I found 24 entries in ICSD for P3122, especially minerals such as
Muscovite 3T but also things like V6C5 and Ag2HPO4 but not Li3MnNiCoO6
Cenzual,
Alan
I agree - I found them as well, but this particular P3112/P3212 group is
very rare. Given that software tends to deal with space group
interpretation on a case-by-case basis it does mean that problems can be
specific to a particular group - especially if it hasn't been tested before.
Some so
Pam,
I hope that when you used GSAS you entered (as per instructions) "p 31 1
2" and not "p3112".
Bob
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Whitfield, Pamela [mailto:[EMAIL PROTECTED]
Sent: Monday, October 18, 2004 12:
Bob
I did indeed - I tried GSAS and it behaves itself.
Pam
Dr Pamela Whitfield CChem MRSC
Energy Materials Group
Institute for Chemical Process and Environmental Technology
Building M12
National Research Council Canada
1200 Montreal Road
Ottawa ON K1A 0R6
CANADA
Tel: (613) 998 8462 Fax:
Pam,
As a developer and someone who uses other software to test against, I
have been following the discussion with interest. This is a complex area
and it goes to show the importance of having a few programs if only for
testing purposes.
I am puzzled by your cif data however as I cant get past ve
AlanI'm afraid that the cif files weren't overly good
ones - I don't normally use them. For the R-3m the Li 1/2 fractional
coordinate is for the z, not y. The structures are related by a Ö3a x Ö3a relationship with Z = 3
for the R-3m and Z = 9 for the P3112.Here are the STR files. You can
Alan,
One of your operators is a typo.
"-x+y, y, -z+1/3" should be " Y-X Y 1/3-Z"
Bob
From: alan coelho [mailto:[EMAIL PROTECTED]
Sent: Mon 10/18/2004 3:16 PM
To: [EMAIL PROTECTED]
Pam,
As a developer and someone who uses other software to test a
Bob
I worked through all of the various operators used in the programs I have
(including Topas) and they are equivalent in each case. Topas works for
this one just as well as GSAS.
Pam
Dr Pamela Whitfield CChem MRSC
Energy Materials Group
Institute for Chemical Process and Environmental Technol
Pam,
Actually you're right! WRT that operator - they are the same. My goof.
Bob
From: Whitfield, Pamela [mailto:[EMAIL PROTECTED]
Sent: Mon 10/18/2004 3:50 PM
To: '[EMAIL PROTECTED]'
Bob
I worked through all of the various operators used in the programs I have
checking
cheers
alan
-Original Message-From: Whitfield,
Pamela [mailto:[EMAIL PROTECTED] Sent: Monday,
October 18, 2004 10:32 PMTo: '[EMAIL PROTECTED]'Subject:
RE: troublesome unit cell
AlanI'm afraid that the cif files weren't overly good
ones - I don
Bob and Pam,
Hope others on the list dont consider this topic as spam but the
checking across programs are a critical part of developent.
and a thanks by myself to the both of them for hand checking the
equivalent poistions - no wonder Bob made a goof.
regards
alan
-Original Message-
F
lan coelho
[mailto:[EMAIL PROTECTED]Sent: October 18, 2004 5:36
PMTo: [EMAIL PROTECTED]Subject: RE: troublesome unit
cell
Pam,
I
looked at your INP file and there was a problem in regards to how atomic
coordinates were defined. As you know TOPAS uses computer algebra with a
out for "apparent" discrepencies.
alan
-Original Message-From: Whitfield,
Pamela [mailto:[EMAIL PROTECTED] Sent: Tuesday,
October 19, 2004 12:05 AMTo: '[EMAIL PROTECTED]'Subject:
RE: troublesome unit cell
Alan
In the original
simulations I used
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