Dear Huang, Just to add that, in our labs when working with Cu Ka1 radiation, we have used Y2O3 for a couple of decades as a standard for instrumental resolution (and hence peak-shape parameters). Typical PXRD patterns are shown in the following web pages, e.g. http://pd.chem.ucl.ac.uk/pdnn/unit1/accurate.htm (XY plot in 2theta) http://pd.chem.ucl.ac.uk/pdnn/inst2/eddcomp.htm (XY plot in 1/d) Y2O3 is excellent for generating lots of well-spaced peaks but it is absolutely *crucial* that it is sintered at high temperature for many days to improve its crystallinity. Even after sintering at 1200C for 5 days, our sample still showed slight broadening when Andrew Fitch measured it for me on the high-resolution PXRD beamline at ESRF (although it showed no broadening in the lab compared to other standards). However, it is not a good standard for checking low-angle peaks as the first peak with significant intensity is at approx. 20 degrees as shown in the patterns. Cheers, Jeremy Karl. p.s. Note that it is not very useful as a standard when working with Mo Ka1 radiation (as used on two of our lab PXRD diffractometers) due to severe fluorescence. *************************************************************** Dr Jeremy Karl Cockcroft Department of Chemistry (University College London) Christopher Ingold Laboratories 20 Gordon Street London WC1H 0AJ +44 (0) 20 7679 1004 (laboratory) [email protected] or [email protected] http://img.chem.ucl.ac.uk/www/cockcroft/homepage.htm ***************************************************************
On Mon, 26 Apr 2021 at 03:16, Huang Liu via GSAS-II <[email protected]> wrote: > Thank you very much for your suggestion. We have Y2O3 in our lab. I will > try it. Thank you very much. > > Best regards, > Huang > ------------------------------ > *From:* GSAS-II <[email protected]> on behalf of > [email protected] <[email protected]> > *Sent:* Saturday, April 24, 2021 10:00:01 AM > *To:* [email protected] > *Subject:* GSAS-II Digest, Vol 303, Issue 1 > > Send GSAS-II mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of GSAS-II digest..." > > > Today's Topics: > > 1. Re: Instrument parameters (Leopoldo Suescun) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 24 Apr 2021 11:53:27 -0300 > From: Leopoldo Suescun <[email protected]> > To: "Toby, Brian H." <[email protected]> > Cc: Huang Liu <[email protected]>, Huang Liu via GSAS-II > <[email protected]> > Subject: Re: [GSAS-II] Instrument parameters > Message-ID: > <CAAeV= > [email protected]> > Content-Type: text/plain; charset="utf-8" > > Hi Brian and Huang, > I use Y2O3 for this purpose. It is not very expensive and got a reasonable > amount of peaks at low angles. In order to minimize size and microstrain > effects, I fire pure Y2O3 for 3 days at 1200 ?C. > I hope it helps. > Leo > > El lun, 19 abr 2021 a las 23:59, Toby, Brian H. via GSAS-II (< > [email protected]>) escribi?: > > > Hi Huang, > > > > First of all Si is not a good standard to use for instrument > > parameters. It has no peaks at low angle. LaB6 is a better choice. If you > > do not have that, perhaps others seeing this can recommend something > > readily available with plenty of sharp peaks. > > > > GSAS-II has no limits on the number of phases that can be read, but > > there was a bug with reading that particular CIF. In it the element > types > > were specified as Ti0, Fe0 and O0 which GSAS-II could not process. I have > > repaired this bug in version #4887. > > > > Brian > > > > On Apr 18, 2021, at 6:04 PM, Huang Liu via GSAS-II <[email protected]> > > wrote: > > > > Hi, > > > > This is Huang Liu from the University of Utah. I am trying to use GSAS 2 > > to do refinement on my data. > > 1. I try to get the instrument parameters according to the tutorial > > ( > > > https://subversion.xray.aps.anl.gov/pyGSAS/Tutorials/CWInstDemo/FindProfParamCW.htm > > ). > > But the U parameters that I get are always negative, and the Rwp is above > > 10. I am using the data generated by*Rigaku mini flex 600 *by *using SRM > > Si 640d* as a standard sample for generating instrument profile > > parameters. The attached file (Si-640d) is the original data. > > Could you please help me generate the instrument profile? Thank you very > > much. > > 2. I try to import Ti2Fe4O phase into the GSAS2, but I failed. > > Since this is the third phase that I want to import. May I ask is there a > > phase quantities limit of import? > > If not, is there anything wrong with my CIF file (I downloaded it from > the > > COD website? > > Attached is the Ti2Fe4O cif card downloaded from COD website. > > I would be very grateful if you can help me. Looking forward to your > reply. > > > > Best regards, > > Huang Liu > > <Si-640d.ras><Ti4Fe2O.cif>_______________________________________________ > > GSAS-II mailing list > > [email protected] > > https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii > > > > > > _______________________________________________ > > GSAS-II mailing list > > [email protected] > > https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii > > > > -- > #YoUsoTapabocas y mantengo #DFS > > Prof. Agr. Dr. Leopoldo Suescun > Cryssmat-Lab/DETEMA, Facultad de Qu?mica, Universidad de la Rep?blica. > e-mail: [email protected] > Tel: (+598) 29290705 > Fax: (+598) 29241906* > Mailing address: > Cryssmat-Lab./DETEMA > Facultad de Quimica > Av. Gral. Flores 2124 > Montevideo 11800 > Uruguay > > Seguime en/Follow me at ResearchGate > https://www.researchgate.net/profile/Leopoldo_Suescun > > ORC*ID*: https://orcid.org/0000-0002-7606-8074 > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://mailman.aps.anl.gov/pipermail/gsas-ii/attachments/20210424/0f951807/attachment-0001.html > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > GSAS-II mailing list > [email protected] > https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii > > ------------------------------ > > End of GSAS-II Digest, Vol 303, Issue 1 > *************************************** > _______________________________________________ > GSAS-II mailing list > [email protected] > https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii
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