[sdpd] strong asymetry refinement

["Guilhem Dezanneau" <gdezano...@inpg.fr>]

i actually have a problem with refinement of manganites synthesised by a spray-pyrolysis
method. Peaks show a high asymetry (right part of the peak larger) even at high angle.
this may come from strain or composition evolution (inherent to the synthesis methos used)
 
i tried to use the asymetry function of the program FULLPROF which gave poor results
i also used the split pseudo-voigt function (number 11) which is very difficult to use 
without diverging...
 
my questions are:
- for the use of this split pseudo-voigt function, is there a practical procedure to avoid 
divergence (i.e. which parameters of this function should i make vary first)
- is the Rietveld method well suited for such a problem i.e. for a probably heterogeneous
powder (i also tried a model including several phases but it increases strongly the number of parameters)
 
thanks
 
guilhem