Dear Charles,
similar problems turned up on the Rietveld list previously. Some time ago I gave a detailed answer to a problem which can be solved in a similar way look at
http://www.mail-archive.com/[EMAIL PROTECTED]/msg01724.html
giving also two references. However, I think your problem is simpler than the previous problem, but please ask once more if the old mail does not clear up your problem.
Best regards Andreas
ling yang wrote:
I have the same question, so post his question here: Dears all, In the structural refinement of ABO3 type, e.g. A1-xCxB1-yCyO3 using GSAS. The dopant (atom C) may be occupied two atomic sites, A and B. Therefore the occupancy constraint should be considered. In order to perform the structural refinement of A1-xCxB1-yCyO3 allowing the occupancies of atom C in the A and B sites to be varied but the total occupancy of atom C must be fixed. How can I define the linear constrain in GSAS? The constraints set as follows, and then how to define the other constraint (g4+g5=fixed)? Would you give me any advice?
# Atom x y z g #1 A x1 y1 z1 g1 #2 B x2 y2 z2 g2 #3 O x3 y3 z3 g3 #4 C x1 y1 z1 g4 #5 C x2 y2 z2 g5
#Phase variable atom no. coeff 1 frac 1 1 1 frac 4 -1 1 frac 2 1 1 frac 5 -1
Thanks in advance, Charles
-- Dr. Andreas Leineweber Max-Planck-Institut fuer Metallforschung Heisenbergstrasse 3 70569 Stuttgart Germany
Telephone: +49 (0)711 689 3365 Telefax: +49 (0)711 689 3312 [EMAIL PROTECTED] http://www.mf.mpg.de/de/abteilungen/mittemeijer/english/index_english.htm
