[Ifeffit] Dodgy Edge Steps

Zajac, Dariusz dariusz.zajac at desy.de
Tue Apr 29 02:03:14 CDT 2008

Hi all,
I want only to add something to your discussion 
first - are we talking about edge step in the linear or logarithmic
scale - ln(3)=~1, so jump ~3 can be ok - if it is in linear scale
second - for higher absorption you can expect the self-absorption
effect, which also decreases the amplitude of EXAFS oscillations. To
correct it you can try to use Menu/ Data/ Self Absorption

	-----Original Message-----
	From: ifeffit-bounces at millenia.cars.aps.anl.gov
[mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of LACHLAN
	Sent: Monday, April 28, 2008 6:28 PM
	To: ifeffit at millenia.cars.aps.anl.gov
	Subject: [Ifeffit] Dodgy Edge Steps
	Hi All
	Long-term lurker, first time poster.
	I've recently collected some EXAFS data with a large edge step
(~3.4) and for some reason didn't pick up on it until it was too late.
I've been told that ideally we would want an edge step of 1 and anything
above ~1.5-2 is too high.  I'm wondering if there is a way to salvage
the dataset in order to compare it with EXAFS data that I collected from
two other samples (all three are supposed to be synthetic goethite).
The first two samples that I want to compare have edge steps of about
	I know Athena allows one to adjust the edge step but wonder how
appropriate this is and how much change this would cause the EXAFS data?
Trying to adjust the edge step from 3.4 down to ~1 or so seems to be
quite a jump.  I'm curious whether there is a way to salvage this data
rather than wait until the next beamrun.
	Any help would be appreciated.

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