you better refine uvw globally for the sample and then Lorentzian x and y individually for each phase. uvw should be constant for a given diffractometer setting and you might get it from an independent refinement of a standard.
best miguel On 3 Feb 2010 at 15:41, Huy LE-QUOC wrote: > Dear Rietvelders, > > I'm currently doing Rietveld refinements (with FullProf) for a > multiphase sample whose 3 phases with space groups Fm3m, P63/m and > I41a/md. The problem is the reflections of these 3 phases are very > superposed and hence I have found that their (U,V,W) refined parameters > seem to be very correlated. > > I have read somewhere that for each phase we should begin refine W, then > V and finally U. But I don't know in my case whose 3 phases having their > own (U, V, W) we should follow which sequence ? First refine (U, V, W) > of the strongest phase and then for others phases? Or should we refine > simultaneously W for all phases and then V and U for all phases? > > > Do anyone of you have any experience on this case ? > > Thank you in advance for your kindly helps. > > Best regards, > > --- > Huy LE-QUOC, > Doctorant > LPSC/CNRS - Centre de Recherche Plasmas-Matériaux-Nanostructures > et Institut Néel/CNRS > 53 rue des Martyrs, Grenoble 38026, FRANCE > > -- Miguel Gregorkiewitz Dip Scienze della Terra, Università via Laterina 8, I-53100 Siena, Europe fon +39'0577'233810 fax 233938 email gre...@unisi.it
