[Ifeffit] RE : problem with Athena's E0 !

Arezki, Bahia Bahia.Arezki at uni-siegen.de
Wed Jul 1 07:26:20 CDT 2009


Thanks for your fast reply !  Actually I have used the data-calibrate tab to calibrate the reference channels. I will check the settings-preferences.


     Dr. Bahia Arezki
        FB7- Festkörperphysik
        Emmy-Noether-Campus, 57072 Siegen
(    +49 2 71/ 740-3713
Ê  +49 2 71/ 740-3763
         Room  ENC- B012
. bahia.arezki at uni-siegen.de
web-site: www.fkp-siegen.de
De : ifeffit-bounces at millenia.cars.aps.anl.gov [ifeffit-bounces at millenia.cars.aps.anl.gov] de la part de Kropf, Arthur Jeremy [kropf at anl.gov]
Date d'envoi : mercredi 1 juillet 2009 14:07
À : XAFS Analysis using Ifeffit
Objet : Re: [Ifeffit] problem with Athena's E0 !

Athena attempts to find a reasonable Eo to make it faster for you to
look at your data.  After that, it is your responsibility to tell Athena
what Eo value to use, and not the other way around.  Some tools are
provided to make it easier to choose consistent values, particularly in
the data-calibrate tab.  Also be aware that several selections in the
settings-preferences tab affect Athena's initial guess for Eo.

Jeremy Kropf

> -----Original Message-----
> From: ifeffit-bounces at millenia.cars.aps.anl.gov
> [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf
> Of Arezki, Bahia
> Sent: Wednesday, July 01, 2009 6:37 AM
> To: Bruce Ravel; XAFS Analysis using Ifeffit
> Subject: [Ifeffit] problem with Athena's E0 !
> Importance: High
> 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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