particularly if texture occurs for one or many phases ! daniel
> > Dear Maria, > > I agree with Dr. Retief, I would never refine structure details like > atomic > coordinates or temperature factor (displacement factors) for QPA! > Regards > Francois Girod > > > > > "Retief, Johannes > \(JJ\)" Pour > :<rietveld_l@ill.fr> > <[EMAIL PROTECTED] cc : > l.com> Objet:RE: > Question on temperature factors > > 01.07.2005 08:50 ZE2 > Veuillez répondre à > rietveld_l > > > > > > Hallo Maria, > > Temperature factors are strongly correlated with surface roughness. > Refining them using X-rays easily lead to rediculously large positive > values or even negative values. My advice would be to fix them at the > theoretical values, especially for the QPA of a complicated system. > > Regards, > > Johannes Retief > > > > -----Original Message----- > From: Maria Chrysochoou [mailto:[EMAIL PROTECTED] > Sent: 30 June 2005 21:55 > To: rietveld_l@ill.fr > Subject: Question on temperature factors > > Hi all, > > I have a question on temperature factors in Rietveld refinement. > I am on working on a complicated system with over 12 phases on > average (it is cement-like in chemistry and mineralogy). I tend not > to refine temperature factors in order to reduce the number of > refinable parameters to a realistic number. > Do you think that the temperature factors make a big difference in > quantitative analysis? Could you give me a range of reasonable > values > for an ambient temperature cement? > > Thank you, > > Maria Chrysochoou > W.M. Keck Geoenvironmental Laboratory > Stevens Institute of Technology > Tel.: +1 201 216 8773 > Fax: +1 201 216 8212 > E-mail: [EMAIL PROTECTED] > > > > > > > > > > NOTICE: Please note that this eMail, and the contents thereof, is subject > to the standard Sasol eMail legal notice which may be found at: > http://www.sasol.com/legalnotices > > > If you cannot access the legal notice through the URL attached and you > wish > to receive a copy thereof please send an eMail to [EMAIL PROTECTED] > > > > > > > > > > -- Daniel Chateigner Professeur CRISMAT-ENSICAEN Bd. M. Juin 14050 Caen, France http://www.ecole.ensicaen.fr/~chateign/danielc/
