Dear all, I've got a problem with the Rietveld refinements of synchrotron data. I'm using Fullprof and the problem is that the overall B, and then also some of the isotropic displacement parameters, fall down to negative values. I'm not very experienced in the treatment of synchrotron data and may be I put some errouneous input in the PCR file, but I cannot understand what.
Thanks in advance for your helpful suggestions, best regards Alberto Martinelli
