[Ifeffit] problem with Athena's E0 !

[Arezki, Bahia]

Hi all,

I am using Athena (version: 08.058) to study the changes in the XANES profiles as a function of temperature of an organometallic compound containing Fe. I have a problem with the E0 value suggested by Athena : I noticed that it is not taking the same maximum in the first derivative. 
I am sending 2 examples of xanes taken at RT ( E0 guessed is 1722.8 eV ) and 10 K  (1727.3 eV !), can any one help me please to solve this problem ? should I  force athena to take the first maximum at 1722 eV ? 
I  tough that  my spectra  have been properly calibrated:  I first calibrated the  iron foil -reference channel (E0=1712 eV) of a sample xanes and then I aligned the rest of the reference channels to that one. I though this was enough to calibrate my data.  can you please tell me if my data processing is correct? 

I need to be sure about the E0 value in order to know the correct shift of the different xanes features as a function of temperature. Also, with a wrong E0 the normalization is not correct...did I miss an important step? 

I am having hard time with these basic questions...before using  linear combination analysis and peak fitting analysis. Of course I have already looked in the IFFEFIT archive, but I did not find such problem. I only found a question about a wrong E0 because taken before the edge which is not my case.  

Thanks so much for your time, 



Bahia
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