[Ifeffit] EuL3-edge-XANES (from one of Bruce's courses)

[Joel Brugger]

Hi,

Looking at the notes from one of Bruce Ravel¹s 2000 EXAFS courses, I noticed
that you used EuTiO3 as an example. My understanding is that this is a Eu++
compound; yet the resonance peak in the XANES spectrum occurs spot on where
I would expect Eu+++ to be, around 6982 eV. As the table below shows (from
Rakovan, J., Newville, M., and Sutton, S. (2001) Evidence of heterovalent
europium in zoned Llallagua apatite using wavelength dispersive XANES.
American Mineralogist, 86, 697-700), the location of the Eu++ resonance peak
does not seem to vary much from compound to compound.

I¹m also joining a figure showing the XANES L3 Eu spectra of EuTiO3 together
with other compounds. The Std spectra shown for comparison are for mixtures
of Eu2O3, W, and WO3 cooked at 1200C in an inert atmosphere, and prepared so
that sample StdB has 20% Eu++, and sample stdC 50% Eu++ (the final product
is a mixture of EuWO4 and Eu2(WO4)2). The growing peak at 6974 corresponds
to Eu++.

Any thought about this discrepancy? Where are the data published?

Thanks in advance for you help,

All the best as ever, JOEL


Ps ­ I cc¹d to Bruce Ravel¹s email address as I don¹t think that the list
takes attachments or embedded figures...




Rakovan, J., Newville, M., and Sutton, S. (2001) Evidence of heterovalent
europium in zoned Llallagua apatite using wavelength dispersive XANES.
American Mineralogist, 86, 697-700.



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