Constraints in GSAS and Fullprof

Francois Goutenoire ( fgo076@hecky.acns.nwu.edu )
Sat, 13 Jul 1996 13:13:15 -0500


Hi, Rietveld users,

I have a serious problem! I am working on a new structure, on X-ray

powder data, with GSAS and Fullprof, and I would like to constrain

my oxygens (8 with x, y, s as variable!!! plus 6 cations for a total

of 36 parameters only for the position).

My oxygens are going everywhere, not very stable and I get too many

short distances (dis<2.5 Angstrom !!). I would like to put constraints

in my model. In fullprof I am very lost, in GSAS this is the same

problem, after I enter the distance and its standard deviation

plus the name of the two atoms, the list option gives me zero constraints

If someboby can give me some help.

Dr. Francois Goutenoire
NorthWestern University
Dept. Chemistry
2145 Sheridan Road, Evanston, Illinois 60208, US

Phone: (847)-491-4228
E-Mail: fgoute@nwu.edu