Hello Simona. Thank you for the tip. Can you please tell me which refined parameters did you mean? I suppose you've meant the Sample Corrections and not the Intstrumental Parameters?
Best regards, Luke Kruszewski > Dear Lukasz, dear all: > > Before eliminating the contribution of the sample to peak broadening (i.e. > before suppressing the CS_L instruction), it would be safer to understand > if the value of 9000 nm is sensible or not. Make sure that there is no > refined variable, in your input, contributing too much to peak broadening. > If this variable exists, the high value of the crystal simply tries to > counterbalance the broadening effect of that variable. > > In this respect, I would follow Peter'suggestion to go carefully through > the correlation matrix provided by Topas when do_errors is at work and > verify if CS_L strongly correlates with some other variable. > > Kind regards, > Simona > > ******************************************************** > Simona Galli, Prof. > Dipartimento di Scienza e Alta Tecnologia > Università dell'Insubria > Via Valleggio, 9 > 22100 Como - Italy > > e-mail: simona.ga...@uninsubria.it > tel: +39-031-2386627 > url: scienze-como.uninsubria.it/sgalli > > Treasurer of the Italian Crystallographic Association > tesori...@cristallografia.org > ******************************************************** > > ----- Messaggio originale ----- > Da: "Cline, James Dr. (Fed)" <james.cl...@nist.gov> > Inviato: 27/07/2016 19:17 > A: "rietveld_l@ill.fr" <rietveld_l@ill.fr> > Cc: ""Łukasz Kruszewski"" <lkruszew...@twarda.pan.pl> > Oggetto: RE: CrySize error in TOPAS > > That means the value is indeterminate with respect to the refinement and > the contribution of "CrySize" [crystallite size broadening] to the > observation is nearly zero. Try turning it off and see what the residuals > do. > > Jim > > > 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: "Łukasz Kruszewski" [mailto:lkruszew...@twarda.pan.pl] > Sent: Wednesday, July 27, 2016 1:08 PM > To: Cline, James Dr. (Fed) <james.cl...@nist.gov> > Cc: rietveld_l@ill.fr; "Łukasz Kruszewski" <lkruszew...@twarda.pan.pl> > Subject: RE: CrySize error in TOPAS > > 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/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > -- 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/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
