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 darek -----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of LACHLAN MACLEAN Sent: Monday, April 28, 2008 6:28 PM To: ifeffit@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 0.35. 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. Cheers Lachlan