RE: Question on temperature factors

[Retief, Johannes \(JJ\)]

Title: Message

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]