[Ifeffit] Projekt with the "flatten-problem"

[Kelly, Shelly D.]

Good going Dave.  I think that you are correct.

Shelly

> -----Original Message-----
> From: ifeffit-bounces at millenia.cars.aps.anl.gov [mailto:ifeffit-
> bounces at millenia.cars.aps.anl.gov] On Behalf Of Barton, David (DG)
> Sent: Thursday, January 11, 2007 10:49 AM
> To: 'XAFS Analysis using Ifeffit'
> Subject: RE: [Ifeffit] Projekt with the "flatten-problem"
> 
> Jens,
> 
> It appears to me that the E-shift is causing the problems with the
step in
> the pre-edge data. Shelly's data only appears to remove the step
because
> the pre-edge and the extrapolated post-edge plots are nearly parallel.
If
> you adjust the Normalization range in Shelly's data you will see the
step
> appear again.
> 
> However, if you set the E-shift to zero and reset Eo, pre-edge range,
and
> normalization range (to your liking) you will see that the step is
goes
> away.  So the work around would be to subtract the E-shift from your
Raw
> data, then import into Athena and do not use any E-shift.
> 
> Bruce or Matt may have to comment, but it appears to me that the
> normalization/flatten routine may not be dealing with the E-shift
> appropriately.
> 
> Dave
> 
> >-----Original Message-----
> >From: ifeffit-bounces at millenia.cars.aps.anl.gov
> >[mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf
> >Of Kelly, Shelly D.
> >Sent: Thursday, January 11, 2007 11:11 AM
> >To: XAFS Analysis using Ifeffit
> >Subject: RE: [Ifeffit] Projekt with the "flatten-problem"
> >
> >Hi Jens,
> >
> >I believe the problem is related to the structure in the data
> >before E0.
> >If you choose e0 to be at the beginning of the structure then
> >the normalization is handled better by Athena.  Take a look at
> >the attached project file.  The first data set with e0 on the
> >edge as you would choose for EXAFS analysis (e1) shows the
> >error that Jens reported.  The second data set with a lower
> >value for e0 at the beginning of the structure (e2) gets the job
done.
> >
> >Cheers,
> >Shelly
> >
> >---------------------------
> >Shelly Kelly
> >Argonne National Laboratory
> >Bldg 203, RM E113
> >9700 S. Cass Ave
> >Argonne, IL 60439
> >
> >Molecular Environmental Science Group
> >www.mesg.anl.gov
> >skelly at anl.gov
> >phone: 630-252-7376
> >
> >
> >> -----Original Message-----
> >> From: ifeffit-bounces at millenia.cars.aps.anl.gov [mailto:ifeffit-
> >> bounces at millenia.cars.aps.anl.gov] On Behalf Of Jens Kruse
> >> Sent: Thursday, January 11, 2007 2:38 AM
> >> To: Athena mailing List
> >> Subject: [Ifeffit] Projekt with the "flatten-problem"
> >>
> >> Hi,
> >>
> >> find attached an example with the "flatten-problem".
> >> thanks a lot,
> >>
> >> jens
> >>
> >>
> >>
> >>
> >> "Hi,
> >>
> >> I have a normalization problem with Athena. If I turn on the
> >"flatten"
> >> option in the background removal section, Athena creates in some of
> >the
> >> normalized spectra a step in the pre-edge range.  How can I  get
rid
> >of
> >> it?
> >>
> >> Thanks,
> >>
> >> jens"
> >
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit