Re: using Zero
Hi. You can do that, of course, but you have to choose: you can use Zero error OR sample displacement, but never use both (this induces some physical impossibilities). However, I assume your diffractometer is calibrated, and the zero position of the detector is fine; the sample displacement may (I suppose) be connected with preparation-derived errors, and I'd use the latter parameter instead of the zero error. Hope this helps anyhow. Good luck! Luke Kruszewski > Dear all, > > I am using Si as internal standard to calibrate my pattern. Should I > refine > the "Zero error" of the diffractometer if I am using the calibrated > pattern? > > Thanks a lot, > > Ana > > > > Dra. Ana Isabel Becerro > > Instituto de Ciencia de Materiales de Sevilla > > CSIC-US > > > > > > > > --- > El software de antivirus Avast ha analizado este correo electrónico en > busca de virus. > https://www.avast.com/antivirus > ++ > 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/ ++
Re: R: CrySize error in TOPAS
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 (1 >> 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 rega
RE: CrySize error in TOPAS
Hi Alan. Thank you for your answer. I will post the list as soon as I get to the program. I always use FP for Peak Type. I also do not use any correction for peak tails (i.e., I do not use Tube Tails, as I do not observe the typical Tube-Tails features). Best regards, Luke Kruszewski > Hi Luke > > The weight percents should not differ if CrySize is irrelevant. Can you > post a list of the weight percents with and without CyrSize as well as > Rwp values. > > Also, what peak type are using; I hope it's not PVII as it can give > incorrect results when the exponent is small leading very long peak tails. > cheers > alan > > -Original Message- > From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On > Behalf Of "Lukasz Kruszewski" > Sent: Thursday, July 28, 2016 3:21 AM > To: Cline, James Dr. (Fed) > Cc: rietveld_l@ill.fr; "Łukasz Kruszewski" > Subject: RE: CrySize error in TOPAS > > Thank you very much, Jim. I do appreciate this. I though it is not > "allowed" not to use the CrySize, maybe because I've mixed crystal size > and crystallite size... However, I did such a single refinement whthout > any CrySize(s) used. The residuals were OK (that is, not much worse than > when using the CrySize, that could possibly overparametrize the refinement > and push it towards the false-correct Rwp etc.), but the wt.% values > obtained differed quite a lot from the ones obtained when using the > CrySize. This difference in wt.% a bit worries me, because I'm working > with TOPAS & Rietveld for some years and I still lack confidence (-; > Patience matters... > > Best regards, > > Luke Kruszewski > > > >> 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 >> 20899-8523USA 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 >>> 20899-8523USA 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 (1 >>> 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 sh
Re: Re[2]: CrySize error in TOPAS
Hello Frantisek! Many thanks for this tip. I use v. 4.0. Best regards, Łukasz Kruszewski > Dear Lukasz, > > I dont no which version of Topas do you use. Just for your information - > the current version Topas 5 enables you to calculate the correlation > matrix > directly from GUI. Just click on "correlation matrix button" a run > calculation. > > Frantisek Laufek > Czech Geological Survey > > > > > > - Původní zpráva - > Odesilatel: "Peter Y. Zavalij" <pzava...@umd.edu> > Příjemce: "Łukasz Kruszewski" <lkruszew...@twarda.pan.pl> > Kopie: "Cline, James Dr. (Fed)" <james.cl...@nist.gov>, rietveld_l@ill.fr > Datum: 2016-07-27 19:23 > Předmět: Re: CrySize error in TOPAS > > 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 20899-8523USA >> 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 (1 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 &
Re: CrySize error in TOPAS
Hello Peter. Thank you very much. I will do so and check it. I find this mailing list very useful - a lot of useful informations from kind people that like to share - thank you! Best regards, Łukasz Kruszewski > 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 20899-8523USA >> > 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 (1 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/ > ++ > > -- 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/ ++
RE: CrySize error in TOPAS
Thank you very much, Jim. I do appreciate this. I though it is not "allowed" not to use the CrySize, maybe because I've mixed crystal size and crystallite size... However, I did such a single refinement whthout any CrySize(s) used. The residuals were OK (that is, not much worse than when using the CrySize, that could possibly overparametrize the refinement and push it towards the false-correct Rwp etc.), but the wt.% values obtained differed quite a lot from the ones obtained when using the CrySize. This difference in wt.% a bit worries me, because I'm working with TOPAS & Rietveld for some years and I still lack confidence (-; Patience matters... Best regards, Luke Kruszewski > 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 (1 >> 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 > -- 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/ ++
RE: CrySize error in TOPAS
Thank you very much, Jim. I do appreciate this. I though it is not "allowed" not to use the CrySize, maybe because I've mixed crystal size and crystallite size... However, I did such a single refinement whthout any CrySize(s) used. The residuals were OK (that is, not much worse than when using the CrySize, that could possibly overparametrize the refinement and push it towards the false-correct Rwp etc.), but the wt.% values obtained differed quite a lot from the ones obtained when using the CrySize. This difference in wt.% a bit worries me, because I'm working with TOPAS & Rietveld for some years and I still lack confidence (-; Patience matters... Best regards, Luke Kruszewski > 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 (1 >> 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 > -- 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/ ++
RE: CrySize error in TOPAS
Thank you very much, Jim. I do appreciate this. I though it is not "allowed" not to use the CrySize, maybe because I've mixed crystal size and crystallite size... However, I did such a single refinement whthout any CrySize(s) used. The residuals were OK (that is, not much worse than when using the CrySize, that could possibly overparametrize the refinement and push it towards the false-correct Rwp etc.), but the wt.% values obtained differed quite a lot from the ones obtained when using the CrySize. This difference in wt.% a bit worries me, because I'm working with TOPAS & Rietveld for some years and I still lack confidence (-; Patience matters... Best regards, Luke Kruszewski > 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 (1 >> 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 > -- 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/ ++
Re: CrySize error in TOPAS
Hello Saul. Thank you for your reply. I've meant the calculated statistical error, that is calculated for each refined parameter in TOPAS; the values themselves seem to be correct, i.e., they are in the limits described as <20, 1>. Best regards, Łukasz Kruszewski > Also do you mean error (as in correct value) or calculated statistical > uncertainty? > > Saul > > On Wed, Jul 27, 2016 at 9:22 AM, "Łukasz Kruszewski" > <lkruszew...@twarda.pan.pl> wrote: >> 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 (1 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 >> >> ++ >> 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/ > ++ > > -- 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/ ++
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 (1 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/ ++
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 (1 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 ++ 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/ ++
Re: The passing of Hugo Rietveld
Indeed, a sad information. A great man gone... The Rietveld method is also one of the ones I use very often. My condolences for the Family. Best regards to all the Rietveld method users. Łukasz Kruszewski > > A sad day indeed for powder diffraction. The impact of Hugo Rietveld's > work can never be overestimated. Developing and applying the Rietveld > method has been central to my work for >30 years. > > Cheers > > > > ooo0ooo > > Ian Madsen > Honorary Fellow > CSIRO Mineral Resources Flagship > Private Bag 10, Clayton South 3169 > Victoria, AUSTRALIA > Phone +61 3 9545 8785 direct > +61 3 9545 8500 switch > +61 (0) 417 554 935 mobile > FAX+61 3 9562 8919 > Email ian.mad...@csiro.au > > ooo0ooo > > From: rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> on behalf of > Alan Hewat <alan.he...@neutronoptics.com> > Sent: Tuesday, July 19, 2016 10:57:44 PM > To: rietveld_l@ill.fr > Subject: The passing of Hugo Rietveld > > The passing of Hugo Rietveld, on the 50th anniversary of Rietveld > Refinement and the 100th anniversary of Powder Diffraction > > It is our sad duty to report the death of Hugo Rietveld at the age of 84 > after a short illness. He leaves behind his wife, a son and two daughters > to whom we extend our heartfelt sympathy on behalf of the more than one > thousand members of the Rietveld Mailing List. > > Hugo was born on the 7 March 1932 in The Hague and migrated to Western > Australia with his family, where in 1957 he enrolled at the University of > WA at the same time as Brian O’Connor and Syd Hall. He obtained his Ph.D. > under the supervision of Ted Maslen who had studied under Dorothy Hodgkin > at Oxford. Hugo pioneered single crystal neutron diffraction at Lucas > Heights Sydney with Terry Sabine, and their first paper was published in > Nature in 1961. > > Clews C J B, Maslen E N, Rietveld H M and Sabine T M (1961) Nature 192 > 154<http://www.nature.com/nature/journal/v192/n4798/abs/192154a0.html> > “X-Ray and Neutron Diffraction Examination of p-Diphenylbenzene" > > Hugo's experience with manual data collection and refinement convinced him > of the need to computerise such tasks, and at Lucas Heights and the UWA he > programmed two of the first IBM-1620 > mainframes<http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP1620.html> > in Fortran-II. After obtaining his Ph.D. in 1964 with Dorothy Hodgkin as > external examiner, (she had received the Nobel Prize for her work on > penicillin and vitamin B12), he joined the neutron diffraction group of > the Reactor Centrum Nederland in Petten and his interest turned to powder > diffraction because large single crystals were not available for the > inorganic materials of interest. > > The young group at Petten including Bert Loopstra, Bob van Laar and Hugo > Rietveld first addressed the problem of overlapping powder reflections by > using a relatively long neutron wavelength (2.6 Å) with a pyrolytic > graphite filter. This spread out the long d-spacing peaks, allowing more > of them to be resolved, and is still a good solution for the magnetic > structures in which they were interested. However, for structure > refinement many peaks were still unresolved, and the shorter d-spacings > needed for high atomic resolution could not even be seen. > > In a 1966 paper, Hugo already used intensities from overlapping Bragg > peaks. Along with others with the same problem, he then tried to fit > multiple peaks to overlapping regions, but with limited success. As well, > a neutron powder pattern took a whole week to collect, and the local > Electrologica-X1 computer<https://ub.fnwi.uva.nl/computermuseum//X1.php> > was less powerful than the IBM-1620 - and programmed in Algol. It was > there and then that the brilliantly simple but profound idea arose of > refining the crystal structure together with the parameters describing the > peak positions and profiles all together, as published in the famous 1969 > paper. > > Rietveld H M (1969) Journal of Applied Crystallography 22 > 65-71<http://scripts.iucr.org/cgi-bin/paper?a07067> > “A profile refinement method for nuclear and magnetic structures” > > Hugo distributed his Algol refinement > program<http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/46/087/46087996.pdf> > widely, but very few papers were initially published using the method. > Discouraged by the limited funding available for neutron diffraction, he > successfully applied
clay mineral samples - illite - interstratified minerals
Dear Rietveld Friends. I allowed myself to attach DOC files with 3 models where I'm trying to provide Rietveld analysis, in TOPAS, for complex clay-bearing sample, which I'm having problems with. In the first model I tried to constrain lattice parameters of illite and biotite, to make TOPAS fit illite's and biotite's reflections to those observed in the qualitative analysis (I'm not sure of the correct position of these minerals' reflections, but both are supposed to be present in the sample). This gives 0% of biotite (it should be present in a small amount)and also cuts the basal peak of montmorillonite, so I removed biotite and changed the Chebychev background fucntion order from 4 to 5, which gave better results (model 2). Then (model 3) I've tried to put both illite and biotite without constraining their lowest/maximum values of lattice parameters and obtained anomalously low (?) amount of biotite. The remaining models are with Peaks Phase to describe the interlayer minerals. With Peaks Phase input the Rwp drops much, but also the amount of illite and kaolinite drops drastically. Also, their relative amounts change much. I'd like to ask, which model would you choose as correct one? I'm sure that there are no instrumental errors, as the geometry has been checked with LaB6 and Si standards. I would be grateful for any help... Best regards! -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) Twarda 51/55 str. 00-818 Warsaw Poland -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) Twarda 51/55 str. 00-818 Warsaw Poland -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) Twarda 51/55 str. 00-818 Warsaw Poland Rietveld_sample.doc Description: MS-Word document ++ 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/ ++
interstratified minerals
Dear Friends. Thank you for your help with glauconite and carbonates. In my clayey samples I also have interstratified minerals, giving assymetric hump. I was trying to calculate its content in TOPAS by using Peaks Phase and then calculating the degree of crystallinity. When doing so, I always obtain lower Rwp but I'm not sure if such treatment is ok and if one should put more than one peak if the hump line is variable? Best regards! Łukasz Kruszewski Polish Academy of Sciences ++ 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/ ++
glauconite/celadonite and carbonates
Dear Friends, I have two questions on PXRD. First, is it possible to distinguish between illite and glauconite and celadonite in a complex mixture containing quartz, illite, muscovite, chlorite and kaolinite (plus some interstratified clay minerals)? I was trying with (060) reflections, and I cannot observe anything with d(060) 1.51, but there is a reflection between 1.50 (that I ascribe to illite) and 1.51, thus I assumed it could be from celadonite. Second question. I use TOPAS (v. 4.0) for the Rietveld refinement. I have samples with dolomite and I know that it is strongly zoned, thus the main reflection is split (dolomite + ankerite). As an input I've used these 2 structures, but both reflections obtained during the refinement lie at the same position, leaving the shoulder non-adjusted (to dolomite). I suppose this result is wrong (?). Do you have any idea how to fit such a shoulder-like reflection in such case? Best regards! -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
multi-mica sample and Rietveld
Dear Friends. I have one more question regarding Rietveld analysis (in TOPAS, v. 4.0). I have multi-mica samples, where muscovite, biotite and illite were observed. There is also a suspiction of the presence of glauconite, thus I am adding this phase into the refinement and this lowers the Rwp value. Is such Rwp lowering a good proof of the presence of glauconite in the sample? Best regards, Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
Re: Does analysis done in Bragg Brentano geometry holds for other geometries?
Hi. The XRD profile (spectrum) does not only depend on the geometry type, but also width of both slits (primary divergence and secondary anti-scatter), symmetric (the same at the primary and secondary part) or non-symmetric solers, the use of any additional optical elements (e.g., we use radial soler instead of the secondary slit), type of detector (the detector slit of the zero-dimensional detector does not have the same physical meaning as the corresponding window of the position-sensitive detector). You cannot hold the B-B geometry in the reflection mode when you go to transmission mode - that is why the second one is used to observe reflections that are not seen (or barely seen) in the previous mode. Peak shape, including its width, would - in some cases - also be different, but peak intensity would especially be affected (in many cases). I would use LaB6 and silicon standards (of NIST SRM) instead of corrections to check the geometry. I'm not an expert in terms of grazing incidence, but I'm pretty sure that is gives much different information, as this is more textural information. Dear Rietvelders Does analysis done in Bragg Brentano geometry holds for other geometries and XRD techniques providing one have diffracted peaks? Are there corrections needed to apply between methods. Say Sheher formula. Dose it holds for peaks reflecting using in-plan grazing incident reflections experiment or it needs to be corrected? Thank you from advance Shay -- _ Dr. Shay Tirosh Institute for Nanotechnology Advanced Materials Bar Ilan University Ramat Gan, 52900 Israel Phone: +972-(0)30-531-7320 Mobile: +972-(0)54-8834533 Email: stiro...@gmail.com _ -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
NAC standard
Dear friends! I have a question regarding the NAC transmission diffraction standard, which is Na2Ca3Al2F14. Is this standard safe in use, i.e., do I need any special safety when grinding it? Best regards! -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
Re: XRF and XRD best practice...
Hi. I think XRF can help only in case of simple samples or, e.g., to disclude some strange elements, by proving there's none of them in the particular sample. But when you have, lets say, a mixture containing a spinel and periclase (MgO), then you won't be able to confirm by XRF itself that all the Mg determined is cointained in periclase only, as spinels take Mg too. An EDS or WDS system would be better here, but of course it gives reasonable results for thin sections mostly. However, even tiny 3D chunks of a sample can be used to confirm the presence of the particular species you've included in the QPA refinement. Good luck! Luke Kruszewski Hello all, I use Rietveld primarily for quantitative phase analysis of rock samples. We collect XRF and XRD data on our samples. Is there a best practice for using these data together? Or a recognized method or procedure for evaluating the agreement between the two? Can the XRF be used to restrain the phase concentrations in a refinement? Thank you all for the years of advice I have gotten from this forum. All the best, Blaise -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
Re: Uiso Beq etc. - calculation problems
Ok - sorry, changed degrees into radians. But there is still a difference for sulphur in aluminite. Best regards, Luke K. OK, here it goes: Uiso = 1/3 * [U22 + 1/sin^2(beta)*(U11 + U33 + 2U13cos(beta)] = 1/3 * [0.01562 + (1/sin^2(110.18))*(0.01937 + 0.01277 + 2* (-0.00027)*cos(110.18)] = 1/3 * [0.01562 + (1/(0.9386)^2) * (0.03214 + (-0.00054)*(-0.345)] = 1/3 * [0.01562 + (1/0.88097) * 0.0323263] = 1/3 * [0.01562 + 1.135 * 0.0323263] = 1/3 * (0.01562 + 0.03669) = 1/3 * 0.05231 = 0.01726 The given Uiso for sulphur is, meanwhile, 0.01621. I have also been trying to calculate Uiso for melanophlogite, which is cubic, co the formula goes: Uiso = 1/3* (U11 + U22 + U33). Using this formula, I have obtained the value of 0.0339, which is exactly the same as the one given in the corresponding CIF file. However, calculating the Uiso using the GENERAL formula gives the value of 0.0287. Both values (0.0339 and 0.0287) were calculated using an EXCEL spread sheet. So how is such a difference possible? Best regards! Luke Kruszewski Dear Łukasz, There must be something wrong with your calculation. A quick examination shows that S must have a higher displacement parameter than Al and that Ueq must be approximately 0.016. I hope this helps. Bob Gould On 10/02/2014 21:50, Łukasz Kruszewski wrote: Dear Rietveld friends, I'm having some problems with calculating Uiso from the anisotropic parameters. Here is an example - I copy first two sites of aluminite (monoclinic): _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 S 0.01937 0.01562 0.01277 -0.00248 -0.00027 0.00954 Al1 0.01117 0.01169 0.01295 0.6 -0.00012 0.00789 Using the formula for Uiso for the monoclinic system, which is: 1/3 * [U22 + 1/sin^2(beta)*(U11 + U33 + 2U13cos(beta)] for the S site we obtain the value of 0,0054 for Al: 0.01225 Meanwhile, the listed Uiso are: _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv S 0.70076 0.37376 0.93018 0.01621 Al1 0.65581 0.45332 0.47633 0.01229 While the author-given value for Al is close to the one calculated myself, the one for S is much different. By the way, 0.01621 * 1/3 = 0.0054. I could find it a simple mistake, I've found such a problem in case of many other structures. And here's my kind question: am I missing something? Best regards! -- Robert Gould Tel.UK: +44 (0)131 667 7230 or +44 (0)796 040 3872 Canada: +1 519 387 8223 --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
Uiso Beq etc. - calculation problems
Dear Rietveld friends, I'm having some problems with calculating Uiso from the anisotropic parameters. Here is an example - I copy first two sites of aluminite (monoclinic): _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 S 0.01937 0.01562 0.01277 -0.00248 -0.00027 0.00954 Al1 0.01117 0.01169 0.01295 0.6 -0.00012 0.00789 Using the formula for Uiso for the monoclinic system, which is: 1/3 * [U22 + 1/sin^2(beta)*(U11 + U33 + 2U13cos(beta)] for the S site we obtain the value of 0,0054 for Al: 0.01225 Meanwhile, the listed Uiso are: _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv S 0.70076 0.37376 0.93018 0.01621 Al1 0.65581 0.45332 0.47633 0.01229 While the author-given value for Al is close to the one calculated myself, the one for S is much different. By the way, 0.01621 * 1/3 = 0.0054. I could find it a simple mistake, I've found such a problem in case of many other structures. And here's my kind question: am I missing something? Best regards! -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
quantitative analysis - perovskites - preferred orientation
Dear Madam/Sir(s), I am performing Rietveld analysis for a sample containing perovskites (CaTiO3 and SrTiO3). When putting-in a preferred orientation (PO) correction (100 direction, as the crystals are cubic-like), I obtain better Rwp and GOF i.e. chi-squared values (9.63 and 1.5, respectively) than in the case of not using this correction (Rwp = 10.62 and GOF = 1.65). However, the values of the PO corrections are higher than the errors calculated. All the other parameters including the graphical fit, background etc., seem to be unchanged. I am also convinced about the correctness of any input, with my diffractometer calibrated with LaB6 and Si standards, and Beq / Uiso parameters taken directly from the CIF files provided, so that the microabsorption factor may likely be rejected (?). My guess is that putting in the preferred orientation might artificially, somehow, make the fit better, maybe due to some interdependence? Could you please kindly suggests if obtaining better statistics (Rwp, GOF) by getting a correction values below the corresponding errors could be treated as a good result? Best regards! -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
Re: Preferred orientation and lattice parameters
Hi! Be careful with LeBail. There is a paper (I can send it to you) showing, that this method may give some errors (so is probably also for Pawley method). Best regards! Btw: preferred orientation should not influence the c parameter, but the intensity of an reflection. It can be influenced by sample displacement or (detector or XRD plane) zero shift, and of course due to impurities. Try Rietveld. Good luck! L. Kruszewski -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) Twarda 51/55 str. 00-818 Warsaw Poland Dear rietvelders, I have carried out the single crystal resolution and the PXRD Le Bail refinement of a Metal Organic Framework. The compound crystalizes as needles and there is a clear in-plane preferred orientation along the c-axis. There is a mismatch between the single crystal and the Le Bail refinement data in the lattice parameter c. Could this mismatch be due to the preferred orientations? Regards, Breogán Pato Doldán, Fundamental Chemistry Department. Faculty of Sciences. University of A Coruña Rúa da Fraga 10, 15008, A Coruña. Spain. Tel: +34 981167000 ext. 2061 ++ 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/ ++
Re: Precision of lattice parameters
Hello Ahmed. It depends on the method you use. For Rietveld, you need quite a lot of parameters, i.e., both sample (structural) parameters and instrumental parameters. Regarding the first group, you have diadochy and defects, that make your sample (or its components) differ from the standards you need to use. But that's what Rietveld does: calculates this difference. More problematic is the way you prepare the sample: the more isogranular is the sample, the better results (i.e., less corrections need to be done by the computer). Also, there is preferred orientation, but this counts for quantitative analysis results rather than unit cell parameters. Regarding instrumental parameters, these are especially the Lorentz-polarization effect, zero of the detector shift (which is physically equal, more or less, to sample displacement - thus, these two parameters CANNOT be used together in any refinement). In general, the better is the sample preparation, the better results you have. Good luck! Lukasz Kruszewski Dear Rietvelders, I am working on the precise measurement of lattice parameters using X-ray diffraction data. Please let me know: 1. Precautions taken during the data recording using XRD. 2. How can we calculate lattice parameters precisely with in the 1x 10-5 nm. 3. It is well known that XRD gives some % of errors, what is the reason behind these errors. Thankyou very much for your time. -- *Dr. Faheem Ahmed * *Post Doc Fellow*- *Engineering Research Centre (ERC)* *School of Nano and Advanced Materials Engineering, Building. No. 54, Room- 322 Changwon National University, # 9 Sarim-dong, Changwon, Gyeongnam 641-773, * *Republic of Korea.* *Email:* faheem...@gmail.com *Ph No*. 0082-55-264-5431 (Office) 0082-10-7263-6411 (Mobile) -- Łukasz Kruszewski, Ph.D., adjunct Polish Academy of Sciences Institute of Geological Sciences X-Ray Diffraction Laboratory (coordinator) 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/ ++
Re: EPM
Hello! I can help in Your chemical data explanation, of course if I manage to (-: Best regards, Luke Kruszewski
Re: give me suggestion
Hello! I'm not conversant with Raman spectroscopy, but I wouldn't recommend EDS analyses for precisely establishing chemical composition, especially if You mean analyzing the 3D (not thin section) samples scanning electron microscope equipped with EDS - it would just be laden with error connected especially with the part of background. I've been trying to recalculate some EDS analyses performed on SEM and only at times it was more or less approximate. EMPA is a very good tool for chemical analyses in microarea, especially for garnets (as its chemical zoning can be analysed very precisely), but good results can sometimes be obtained also for 'difficult' (i.e. fine-grained) minerals like clay minerals. I think the best way for defining the unit cell parameters would be to get them from PXRD of the samples, i.e. using TOPAS program. With best regards, Lukasz Kruszewski
TOPAS full axial model
Hello to all! My name's Lukasz Kruszewski, my interest recently is the mineralogy of burning coal dumps. I'm trying to obtain the unit cell parameters of some members of the alunite group, analysed on Bruker D5005 diffractometer (Co Ka, Bragg-Brentano, RS = 0.6mm wide, FDS = 1 deg.) with use for an article. I pack powdered samples as thin layer on a glass slide with limiters. I would like to kindly ask for help in understanding well the FULL AXIAL MODEL in the INSTRUMENT section of TOPAS program. I know that the SOURCE LENGTH, SAMPLE LENGTH and RS length should be FIXED, but I don't know actually does the SAMPLE LENGHT means. Do I understand well that its the length of the beam focusation area only, or the whole length of the glass slide, or the 'working' distance between source and detector? I would be grateful for any tips (-: With best regards, Lukasz Kruszewski Instutite of Geochemistry, Mineralogy and Petrology Faculty of Geology University of Warsaw
Re: TOPAS full axial model
Roberto R. de Avillez napisał(a): Hi Lukasz, You are talking about fundamental parameters approach to Rietveld as proposed by Alan Coelho (CHEARY, R. W. e COELHO A., J. Appl. Cryst.,31, 1998, 851-861. ) The sample length is the length of the sample measured in the axial direction (in mm). It is the illuminated area, so it must depend on the source length if you consider the axial divergence. I usually fit all the fundamental parameters using a diffraction from a standard sample and making restrictions for the allowed variations. Then I use the fitted values as the instrument parameters for my samples that use the same geometric arrangement. Best regards, Roberto de Avillez Łukasz Kruszewski escreveu: Hello to all! My name's Lukasz Kruszewski, my interest recently is the mineralogy of burning coal dumps. I'm trying to obtain the unit cell parameters of some members of the alunite group, analysed on Bruker D5005 diffractometer (Co Ka, Bragg-Brentano, RS = 0.6mm wide, FDS = 1 deg.) with use for an article. I pack powdered samples as thin layer on a glass slide with limiters. I would like to kindly ask for help in understanding well the FULL AXIAL MODEL in the INSTRUMENT section of TOPAS program. I know that the SOURCE LENGTH, SAMPLE LENGTH and RS length should be FIXED, but I don't know actually does the SAMPLE LENGHT means. Do I understand well that its the length of the beam focusation area only, or the whole length of the glass slide, or the 'working' distance between source and detector? I would be grateful for any tips (-: With best regards, Lukasz Kruszewski Instutite of Geochemistry, Mineralogy and Petrology Faculty of Geology University of Warsaw -- Muchos Gracias Roberto! You have helped me very much! Good luck in Your work! Cheers, Lukasz K.
