If you switch from GUI mode to launch mode and perform refinement, you will see correlation matrix at the end of .inp file and can tell which parameters correlate a lot and figure out what's causing such large error. I also think that this error is not strange for such large cryst.size as it is basically beyond the limt of the methods. Peter
.................................................................... Dr. Peter Y. Zavalij Director - X-ray Crystallographic Center University of Maryland, College Park, MD 20832 On Wed, Jul 27, 2016 at 1:07 PM, "Łukasz Kruszewski" < lkruszew...@twarda.pan.pl> wrote: > Hello James. I just read the error that is reported for each refined > parameter in TOPAS. I obtain value like, e.g., 9000 nm, and the error is, > e.g., 205006. > > Best regards, > > Łukasz Kruszewski > > > > By what metric are you determining that the CrySize value is in error? > > > > > > James P. Cline > > Materials Measurement Science Division > > National Institute of Standards and Technology > > 100 Bureau Dr. stop 8520 [ B113 / Bldg 217 ] > > Gaithersburg, MD 20899-8523 USA > > jcl...@nist.gov > > (301) 975 5793 > > FAX (301) 975 5334 > > > > -----Original Message----- > > From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On > > Behalf Of "Lukasz Kruszewski" > > Sent: Wednesday, July 27, 2016 10:22 AM > > To: rietveld_l@ill.fr > > Subject: CrySize error in TOPAS > > > > Dera friends, > > > > I'm doing Rietveld refinements in TOPAS; I get rather good fit of the > > reflections, rather good wt.%, but I've observed large errors for the > > CrySize (Lorentzian) values for some introduced Structures. I've tried to > > change it by refining CrySize (Gaussian), but it only changed in few > > particular cases. I'm rather sure that the intrumental parameters > > (geometry of the diffractometer was analyzed with the use of LaB6, Si, > and > > other standards) and corrections (sample displ. etc.) are OK and I > suppose > > these factors shouldn't influence (?) the CrySize values. I always > > constrain the minimum (20 starting value) and maximum (10000 nm) value > for > > CrySize; I usually refine strain, but I've noticed that it doesn't > > influence the results (at least the wt.% calculated). Rwp, goodness of > fit > > and Durbin-Watson statistics R values are OK; also, the calculated > > background line is "flat", i.e., there is no mistaking of the background > > with reflections; the shapes of the reflections in the calculated > > diffractograms seem to be OK, too. I was thus wondering if these high > > errors coming from the CrySize are that important for the refinement? > > > > Best regards, > > > > > > -- > > Łukasz Kruszewski, Ph.D., adjunct > > Polish Academy of Sciences > > Institute of Geological Sciences > > Twarda 51/55 str. > > 00-818 Warsaw > > Poland > > > > > -- > Łukasz Kruszewski, Ph.D., adjunct > Polish Academy of Sciences > Institute of Geological Sciences > Twarda 51/55 str. > 00-818 Warsaw > Poland > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > >
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
