Hi,
On Tuesday 11 July 2006 19:13, Whitfield, Pamela wrote:
> After spending over 2 days making up a single file, I'd like to hear some
> other opinions on the practical aspects of CIF files for structures from
> powder data. This is partly a moan from trying to get a 11000 line file to
> pass the CheckCIF when all of the items it complains about are actually
> there from what I can tell. Although optimizing data collection using
> VCT-type approaches is nice from a statistics point of view, it's absolute
> hell when it comes to creating the CIF file, and multiple phases just piles
> on the grief. I almost wish I hadn't bothered with the internal standard.
As for VCT, is there really a specific need to write everything ? The only
useful information is, for each point "2theta (or d or t), Iobs and
sigma(Iobs)".
After all, the 'VCT' information is entirely included in
sqrt(Iobs)/sigma(Iobs), which can be constant or not, so why bother writing
the exact counting time for each point, even if the powderCIF dictionnary
allows it ?
Vincent
--
Vincent Favre-Nicolin
CEA/Grenoble http://www-drfmc.ceng.cea.fr/
DRFMC/SP2M/Nano-structures et Rayonnement Synchrotron
17, rue des Martyrs
38054 Grenoble Cedex 9 - France
tél: (+33) 4 38 78 95 40 fax: (+33) 4 38 78 51 97
--
Vincent Favre-Nicolin
Université Joseph Fourier
http://v.favrenicolin.free.fr
ObjCryst & Fox : http://objcryst.sourceforge.net
