EuL3-edge-XANES (from one of Bruce's courses)
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.
On Sunday 04 March 2007 17:57, Joel Brugger wrote:
Any thought about this discrepancy? Where are the data published?
Joel, The only place I ever did anything with those Eu data is in my thesis. Those are the only Eu edge data I have ever measured and that was almost 12 years ago. I found the raw data file, which is attached, for the data you showed in your figure. As you can see, we did not measure a reference, so there is some ambiguity about calibration. I'm sorry I don't have anything more useful to tell you. The measurement is just way outside my living memory and I have much less experience with Eu than you do. I believe I still have the sample. If you would like to discuss borrowing it, we can do so off the mailing list. B -- Bruce Ravel ---------------------------------------------- bravel@anl.gov Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/
participants (2)
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Bruce Ravel
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Joel Brugger