[Ifeffit] Energy Resolution

Julian Ehwald jehwald at gmail.com
Wed May 9 02:24:27 CDT 2018

Hi Carlo

Thank you very much for your answer! If you say it is sufficient to use
dk=0.05, that means I would be able to collect a full EXAFS spectra (k=0 to
12) in only 250 datapoints? That would save us a lot of time!

Best, Julian

-----Ursprüngliche Nachricht-----
Von: Ifeffit [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] Im Auftrag
von Carlo Segre
Gesendet: Sonntag, 6. Mai 2018 01:07
An: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
Betreff: Re: [Ifeffit] Energy Resolution

Hi Julian:

With an edge energy of 543 eV, your monochromator resolution should be at
least 0.1 eV.  If you are interested in XANES, you need to take data at this
resolution or maybe even better.  ONce past the edge, there is no need to
keep that step size.  If your beamline permits an EXAFS-type step scan with
steps in k-space, you want to use a dk of 0.05 which is what IFEFFIT
interpolates to.  Smaller step sizes are not really useful.


On Sat, 5 May 2018, Julian Ehwald wrote:

> Dear all,
> This might be a very general question, but: I was wondering what 
> energy resolution you typically use at beamlines to obtain your raw data
for exafs.
> Since we have limited Beamtime only and other experiments that we want 
> to carry out, I was wondering what kind of resolution is common. Or
> differently: Is it predictable what happens if I for example change 
> from steps of 0.2eV to 0.4eV? We want to obtain spectra up to 500eV 
> above Oxygen K, if that is of relevance.
> Best, Julian

Carlo U. Segre -- Duchossois Leadership Professor of Physics Interim Chair,
Department of Chemistry Director, Center for Synchrotron Radiation Research
and Instrumentation Illinois Institute of Technology
Voice: 312.567.3498            Fax: 312.567.3494
segre at iit.edu   http://phys.iit.edu/~segre   segre at debian.org
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