Dear Kurt, It seems that the problem is in wrong sample-to-detector distance which results in the nearly linear angular dependence of the peak displacement.
Regards, Leonid ********************************************************* Leonid A. Solovyov Institute of Chemistry and Chemical Technology 660049, K. Marx 42, Krasnoyarsk, Russia www.icct.ru/eng/content/persons/Sol_LA www.geocities.com/l_solovyov ********************************************************* --- On Thu, 1/8/09, Kurt Leinenweber <ku...@asu.edu> wrote: > (I hope this list is appropriate for this question). I am > trying to set > up a new D8 diffractometer from Bruker, and have it set up > with a Vario > monochromator focusing on a sample in a capillary. Of > course I hope to > do Rietveld refinement on the samples eventually. But > there is an error > in two theta of the peak positions on all samples, and the > error is > linear in two theta. At 40 degrees the error (measured > minus expected) > is about 0.020 degrees, at 80 degrees the error is about > 0.040 degrees, > etcetera. > > > > Has anyone ever seen anything like this and do you know > where it could > come from? > > > > Thank you very much, > > > > > - Kurt > > > > > > ********* > > Kurt Leinenweber > > Dept. of Chemistry and Biochemistry > > Arizona State University > > Tempe, AZ 85287-1604 > > > > phone (480)-965-8853 > > fax (480)-965-2747 > > > > ***********