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Re: [sdpd] Extracting Fobs using LeBail technique
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>My problem is, in the LeBail mode, the Fobs are not the same for Ka1 and Ka2
>in REFLIST. Therefore I can't use them. Does anyone know how to get around
>this? Thanks,
The original code (ARIT program) takes care of this by calculating
the average (Ka1+Ka2) "|Fobs|" at each iteration, which is injected
as the new Fcalc for the next iteration, with the right Ka1/Ka2 ratio.
Apparently this is not done in GSAS... How different are those Ka1
and Ka2 "|Fobs|" ? I can imagine that after 20 iterations, the values
will possibly diverge enormously, unless the pattern is quite simple
with well resolved doublets.
Solution :
Either correct your pattern from the Ka2 component before structure
factor amplitudes extraction (this may introduce ripples and noise),
or use a Rietveld program doing the job correctly : Fullprof, WinMProf,
etc, or even, use the Pawley method instead of mine. See a program list
at : http://www.cristal.org/iniref/progmeth.html
Best,
Armel Le Bail
http://www.cristal.org/