Re: unit cell refinement

Srebri Petrov ( spetrov@alchemy.chem.utoronto.ca )
Wed, 18 Mar 1998 15:04:17 -0500 (EST)

At 12:29 AM 3/18/98 +0900, you wrote:
>Hello all,
>
>Lately I started to add a unit cell refinement routine to the program Convert.
>It seems to work now but I want to test it on some "real world cells". So I
>would be grateful if you could send me some data for testing (preferably not
>simulated). The program accepts internal standard, zero and wavelength
>corrections, the data should be in 2theta, theta or d.
>Thanks,
>N
>
>--
>Nita DRAGOE
>http://www.hongo.ecc.u-tokyo.ac.jp/~tdragoe
>____________________________________________________
>

Hi, Nita,

If you remember I contacted you for some conversion routine for files
transformation for GSAS 3 years ago. Since then I have really enjoyed your
excellent Convert 2.0. Now, I am glad that you will make something for unit
cell parameters refinement. My strong opinion is that we (PXRD people) badly
need more and efficient lattice calculation routines. I agree with Armel and
the others that one can get the highest accyracy unit cell data from
Rietveld (I did it myself few times), but in my everyday work I very often
am asking to refine uc-parameters for compound(s) that are isostructural
each other, but change their lattice's dimensions. Almost every week I have
few samples to refine. I am using an old Appleman & Evans PD-DOS version for
that and I am sure that you are doing the right job and I will be able to
use it soon. The only problem is that I am still running Windows 3.11, so is
it possible to make a version for it as well? Antyway, I wish you good luck,
aand keep me imformed.
For some testing purpuses, I am sending you few of the hundresds input files
that I have. These are DOS -files containing enough number of reflections. I
choosed 6 files which represent different symmetries and lattices. The
d-spaces are from the real samples that I run purposly for lattice
measurement. Some of the data are not measured with a sufficent precision,
but you can try them if you want. I am also providing you the final results
that I got from the Appleman & Evans routine. Enjoy!!!

File System a b c beta

1. GES2.INP TETRAG 11.0474(8) - 18.7235(14) -
2. DOLOMITE.INP HEXAG 4.8100(2) - 16.0279(10)
3. QUNSNS_1.INP ORTHO 13.1020(8) 17.8334(13) 23.2022(13)
4. DABSNS1.INP MONOC 22.4555(33) 13.4342(22) 17.3789(28) 105.25(2)
5. TJE96SL.INP MONOC 10.3041(18) 13.3240(21) 20.2704(32) 91.06(2)

Regards,

Srebri Petrov

Attachment Converted: "c:\program files\eudora\attach\GES2.INP"

Attachment Converted: "c:\program files\eudora\attach\DOLOMITE.INP"

Attachment Converted: "c:\program files\eudora\attach\QUNSNS_1.INP"

Attachment Converted: "c:\program files\eudora\attach\DABSNS1.INP"

Attachment Converted: "c:\program files\eudora\attach\TJE96SL.INP"

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Dr. Sr. Petrov/PXRD Analyses,
Dept. of Chemistry, U of T,
80 St.George Str., R.417
Toronto ON M5S 3H6, Canada
Tel/Fax: (416)-978-1389.