Shelly, I agree that Athena applies its (her) algorithm correctly. Whether that algorithm is correct may be a matter of opinion. The apparent discrepency Lisa sees is due to Athena's algorithm: i.e., fit preedge line, fit postedge function to normalization range, extrapolate both functions to edge energy to find edge step. Another option would be to fit predge line and subtract it. After that, fit the post edge normalization range. With Athena, if there is a non-zero slope to the preedge line and you choose norm order 1, you get Lisa's result. With normalization order 2 or 3, the results should either be the same, or at least, much closer. Jeremy
-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Kelly, Shelly Sent: Monday, October 26, 2009 9:08 AM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] Normalization in Athena
Hi Lisa,
Be sure that Athena has been rigorously tested and she does know how to normalize data. It is much more likely that the default values are not the "best" ones for your data.
My book chapter goes over how Athena normalizes data in detail. If you send me your email address I'll send you a copy. In particular see figure 14-16.
Cheers, Shelly dr.sdkelly@gmail.com
-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit- bounces@millenia.cars.aps.anl.gov] On Behalf Of Gudrun Bovenkamp Sent: Monday, October 26, 2009 8:42 AM To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Normalization in Athena
Hey everybody,
while I try to figure what effect normalization has on Linear combination fitting in my lead L3 edge XANES system, I came accross this problem: Athena does not normalize correctly:
Normalization in Athena (post-edge): using 1.order normalization, no flattening (which in this case is irrelevant anyway), points +199 eV and +200 eV above E0.
Normalization in Origin (post-edge): using point 13235 eV (+200 eV above E0); dividing the spectrum column by that value.
See the two examples in the attachment.
In both examples the normalized spectrum imported from Athena does not have the norm value of 1 at 13235 eV. Why is that? The offset is also not the same for every spectrum. That undoes the normalization routine.
Greetings, Lisa
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