[Ifeffit] Problems in Energy calibration

Lei Zhong leizhong8532 at gmail.com
Wed May 14 15:23:25 CDT 2014


Dear all,

we had beam line time in DESY (Hamburg) and ERSF (Grenoble) for NiMo
sulfided supported samples. In DESY we got quite nice foil reference but in
ERSF we failed since the third chamber showed problems. Therefore, we have
critical issues to do the energy calibration for spectra collected from
ERSF. We collected spectra for MoS2 crystals. So we are thinking about if
it is reasonable to compare the spectra of MoS2 for the energy shift and
further apply the energy calibration. Would you please give me suggestions?
Thank you in advance.

Q1. In two beam lines, for exactly the same MoS2 crystal, we got difference
in XANES region. Spectrum from DESY has a weak preedge peak resolved in
XANES while ERSF doesn't. And the derivative shape of the two spectra for
MoS2 collected from two synchrotrons are not well overlapped. Is it
acceptable?

Q2. I tried to overlay the first derivative of the two spectra of MoS2.
There is a energy shift at 2.5 eV from the different synchrotrons if we
take the one from DESY as standard. Can I apply the energy shift at 2.5 eV
for MoS2 from ERSF and then overlay the first derivative of the other NiMo
samples with MoS2 to get the energy calibration? Or should I apply 2.5 eV
for all the NiMo sulfided samples?

Q3. Since we lost the signal for the foil reference in ERSF, we tried to
put the foil in the sample position. The first derivatives of the foil
spetra from time to time overlap quite well. Should we set the energy
calibration at 0 according to the stable foil signal?

Sorry for the long email. Thank you for the time reading it. Hopefully I
made the questions understandable to you. Looking forward to your answer!

Thanks.

Regards,
Lei
Technical University of Munich
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