[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [sdpd] calibration problems with Silicon+gsas
Hi,
we have been using Stoe Stadi_P for 16 years and have never encountered
problems with positioning. My advice for you is to read
technical manual, part calibration ... Second, changing the origin of a
spgr can hardly change indicated positions of the Bragg diffractions, so
there is not the problem ...
lubo
On Tue, 10 Jun 2008, Lujun...@EKM wrote:
> Hello, All:
>
> Thanks to the suggestion from Prof. Gottschalk, i took (1/8,1/8,1/8) origin instead of (0,0,0). It is much improved and it shows the calibration sample has no problem, but current match cannot be better enough.
>
> Nevertheless, whether the device's state was suitable for refinement analysis or not is still unclear, and i still doubt whether the peakshapes produced by the device can be well descriped by type-3 parameters.
> Moreover, i am also doubting whether this rough parameters, as shown in the webpage, are somehow reproducible for other materials when all the measurement conditions are the same.
>
> The discussion webpage has been updated, please see more pictures via:
> http://www.physik.uni-augsburg.de/~lujun/
>
> Faithfully
> Jun Lu
> ----------
> Lst. Prof. Lijie Qiao
> Department of Materials Physics and Chemistry
> University of Science and Technology Beijing
> 100083 Beijing
> P.R. China
> http://www.instrument.com.cn/ilog/handsomeland/
>
> Lst. Prof. Loidl and Lunkenheimer
> Experimental Physics V
> Center for Electronic Correlations and Magnetism (EKM)
> University of Augsburg
> Universitaetsstr. 2
> 86159 Augsburg
> Germany
> http://www.physik.uni-augsburg.de/exp5
>
> ----- Original Message -----
> From: Matthias Gottschalk
> To: sdpd...@yahoogroups.com
> Sent: Tuesday, June 10, 2008 6:58 PM
> Subject: Re: [sdpd] calibration problems with Silicon+gsas
>
>
> In spacegroup F d 3- m there a 2 origins.
> Put the Si on 1/8 1/8 1/8 instead of 0 0 0.
>
> The Stadi P is a brilliant instrument (curved Ge
> monochromator, PSD). We use it (2 of them) in conjunction
> with GSAS now for 14 years without problems. However some
> crystallographic knowledge helps when doing Rietveld
> refinements.
>
> Matthias Gottschalk
>
> On Tue, 10 Jun 2008 17:09:03 +0200
> "Lujun...@EKM" <jun.lu...@physik.uni-augsburg.de> wrote:
> > Hello, crystallographical experts:
> >
> > i had never got a satisfying refinement solution for
> >my interesting materials, so i began to doubt our X-ray
> >device (STADI-P, STOE Company): was it capable of
> >structural refining or just not well calibrated? This is
> >the motivation for my calibration refining work.
> > The raw data was collected and can be easily indexed.
> >i was happy for a while, but when the refinement work was
> >tried, i became dispointed. Whatever i tried, the match
> >betrween raw data and calculation was always bad: there
> >were no calculation intensities in some positions where
> >should be, and in other positions also were there no
> >experimental peaks where should be.
> > Would anyone like to point out some reasons for such
> >situation? In particular, the most important question for
> >me is whether our STADI-P device suitable for refinement
> >experiments or not. If so, i have no choice but to throw
> >away all my previous refinement work. :(
> >
> > All the related files has been attached along with this
> >mail (raw data with raw format, gsas format and ascii
> >format; instrument data where parameters are estimated
> >using CMPR programme; one well-cited published CIF file
> >for silicon; and the hkl files after indexing with
> >PowderX).
> >
> > Your reply will be quite appreciated.
> >
> >
> >
> >Faithfully
> > Jun Lu
> > ----------
> > Lst. Prof. Lijie Qiao
> > Department of Materials Physics and Chemistry
> > University of Science and Technology Beijing
> > 100083 Beijing
> > P.R. China
> > http://www.instrument.com.cn/ilog/handsomeland/
> >
> > Lst. Prof. Loidl and Lunkenheimer
> > Experimental Physics V
> > Center for Electronic Correlations and Magnetism (EKM)
> > University of Augsburg
> > Universitaetsstr. 2
> > 86159 Augsburg
> > Germany
> > http://www.physik.uni-augsburg.de/exp5
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/sdpd/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/sdpd/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:sdpd-digest...@yahoogroups.com
mailto:sdpd-fullfeatured...@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
sdpd-unsubscribe...@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/