[sdpd] Fullprof error messages

[Cora Lind <cl284...@cornell.edu>]

Dear all,

I am trying to do a 2 phase refinement in Fullprof (Si as internal 
standard, and profile matching for an indexed but otherwise unidentified 
phase). I have adjusted several values manually in order to obtain a 
semi-decent starting match. Refining the scale factor of the standard as 
the only variable, I obtain Bragg R-values of 0.21 and 0.13 for the 2 
phases. However, if I try to vary anything else (while either fixing or not 
fixing the scale factor), I get one of the following 3 error messages:

i) If I try to refine a profile parameter for the standard (e.g. U, V, W), 
I get a "singular matrix" error.
ii) If I try to refine the zero point, I get a "no reflections found - 
check your input data" error and a pattern that looks like zero and 
infinity (or something outside the plotting boundaries) as the only values.
iii) If I try to vary the lattice constants of my unknown phase, the 
R-values of both phases jump to 98 and then "NA".

Any ideas what might be wrong, and how I could fix it?

Thanks in advance,

Cora

*******************************************
Cora Lind

Department of Chemistry & Chemical Biology
Baker Laboratory
Cornell University
Ithaca, NY 14853-1301

Phone:	(607) 255-4164 (W)	(607) 257-6954 (H)
Fax:		(607) 255-4137 (W)	(607) 257-6954 (H)

e-mail:	cl284...@cornell.edu
*******************************************


 

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