Re: [sdpd] help on Rietveld refinement

[Armel Le Bail <alb...@cristal.org>]

Hello,

>As a beginner in pattern fitting and Rietveld refinement, I am running into
>problems.  The sample is a gamma (or eta) Al2O3 powder (with minor alfa
>phase, which is corundum).  Because of severe peak broadening, I can't even
>get a semi-satisfying fit.  I desperately need help from experts in the
>field.

Well, your pattern shows bad statistics and strong anisotropic
broadening. Even an experienced user of the Rietveld method
has problems with that. Moreover, eta/gamma/delta alumina
is not trivial structure...

Being given that the size/strain round robin is still stuck on
a simple case of isotropic size broadening, my advice would be
to read the latest IUCr CPD Newsletter No28 (and the very
similar No24) at :
http://www.iucr.org/iucr-top/comm/cpd/Newsletters/
and to contact expert people having presented a paper about
microstructure there.

Best wishes,

Armel

    


------------------------ Yahoo! Groups Sponsor ---------------------~-->
Make Money Online Auctions! Make $500.00 or We Will Give You Thirty Dollars for Trying!
http://us.click.yahoo.com/yMx78A/fNtFAA/i5gGAA/UIYolB/TM
---------------------------------------------------------------------~->

 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/