Vincent and co Unfortunately I don't yet have the software to do a real VCT data-collection (not sure many people do, hence 'VCT-type'). Until I can do it properly, the best I can do is chop the pattern up into pieces with different count-times (and sometimes step-size at high angles), and treat them as multiple datasets :-( Easy enough to deal with in the refinement but more than a couple gets clumsy to deal with in the CIF.... This is the first one of these files I've had to make up, and because I intend submitting to a IUCr journal I can't skip too many of the fields (which includes the data, calculated, reflections, etc, which do work BTW). To cover all my bases I've put this through every CIF-editing/checking piece of software I can get my hands on. Some of them give no errors whereas some light up like a Christmas tree, e.g. Platon. Next week I have to make another file with resonant diffraction and neutron data thrown in with anisotropic broadening and some very complex occupational constraints - I have to say that after this experience I'm not looking forward to it, although that one will be going to Elsevier so maybe they won't miss a few terms! Pam
________________________________ From: Favre-Nicolin Vincent [mailto:[EMAIL PROTECTED] Sent: Wed 12/07/2006 5:30 AM To: rietveld_l@ill.fr 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 <http://v.favrenicolin.free.fr/> ObjCryst & Fox : http://objcryst.sourceforge.net <http://objcryst.sourceforge.net/>
<<winmail.dat>>
