[sdpd] Rietveld refinement

["a.mahres" <M.amri...@warwick.ac.uk>]

Dear All,

I'm a new user of rieveld refinement.
In my work I want to refine the structure of zeolite Si24O48 from
synchrotron data at diffrent temperatures
I have refined firstly the unit cell using fullprof(profile matching
with constante scale factor) at each temperature. after I added to
each PCR file the atomic positions from ICSD model with bond and 
angles restraints.

I have a problem with the intensities and I can't refine the 
isotropic thermal parameters they gives negative values.
I trayed the refinement with fixed values of isotropic thermal
parameteres but the intensities are low; the calculated model dont 
fit well the experimental pattern.  

could you help me please.

Regards

Mahrez




 
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