2005
DOI: 10.1016/j.elspec.2005.01.177
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Electronic structure and valence state of CeAl2 from X-ray absorption and emission spectroscopy

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Cited by 7 publications
(7 citation statements)
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“…NEXAFS total electron yield (TEY) spectra of the M 5,4 edges, probing the near surface regions of a few nanometers, demonstrated the reduction of CeO 2 under ambient pressures of H 2 (20 mbar), mediated again by the Pt (Figure ). Low energy M 4,5 features, consistent with those of the Ce 3+ reference, , are apparent in the NEXAFS spectrum obtained in H 2 at 200 °C. The linear combination fit using the reference CeAl 2 (Ce 3+ ) and CeO 2 (Ce 4+ ) indicated about 26 ± 1% atom Ce 3+ at 200 °C and about 34 ± 1% atom Ce 3+ at 250 °C.…”
Section: Resultssupporting
confidence: 72%
“…NEXAFS total electron yield (TEY) spectra of the M 5,4 edges, probing the near surface regions of a few nanometers, demonstrated the reduction of CeO 2 under ambient pressures of H 2 (20 mbar), mediated again by the Pt (Figure ). Low energy M 4,5 features, consistent with those of the Ce 3+ reference, , are apparent in the NEXAFS spectrum obtained in H 2 at 200 °C. The linear combination fit using the reference CeAl 2 (Ce 3+ ) and CeO 2 (Ce 4+ ) indicated about 26 ± 1% atom Ce 3+ at 200 °C and about 34 ± 1% atom Ce 3+ at 250 °C.…”
Section: Resultssupporting
confidence: 72%
“… a Values for Th 4+ are from ref . b Values for Th 4+ and Ce 4+ are from ref , and values for Pr 3+ are from ref . c p M = −log [M] free ; [M] tot = 10 –6 M; [L] tot = 10 –5 M. …”
Section: Resultsmentioning
confidence: 99%
“…Ce can be found in the 4+ formal oxidation state in some nonmolecular, extended solids such as Cs 2 CeCl 6 and other binary halides, CeO 2 , Ce­(SO 4 ) 2 , and [NH 4 ] 2 [Ce­(NO 3 ) 6 ], , among others . These materials have been the subject of numerous synchrotron-radiation-based spectroscopy experiments, including X-ray photoelectron spectroscopy, resonant inelastic X-ray scattering, and X-ray absorption (XAS) spectroscopies at the Ce L 3 -, ,, M 5,4 -, ,, and N 5,4 -edges, as well as ligand K-edges. , Some of these studies have presented evidence for the importance of both 4f- and 5d-orbital contributions to the covalency in Ce bonding. ,, Extended solids including CeO 2 have also served as important test cases for evaluating whether accurate theoretical methodology can treat the 4f electrons simply as part of the core or whether a more demanding approach should be followed that allows the 4f electrons to delocalize and participate in bonding. Ce intermetallics have been at the forefront of condensed matter physics and development of the Anderson impurity model for heavy Fermion systems and Kondo insulators . For example, Ce L 3 - and M 5,4 -edge X-ray absorption near-edge structure (XANES) spectroscopic investigations of CeRu 3 , CeRh 3 , and CePt 3 have provided evidence for 4f-electron delocalization, ,,, and L 3 -edge investigations of intermetallics such as CeCoIn 5 have led to a new understanding of their remarkable magnetic and superconducting properties. The pace of synthetic, experimental, and theoretical progress has been impeded recently because of sample purity concerns, u...…”
Section: Introductionmentioning
confidence: 99%
“…μ-XAS of the as-prepared island (bottom spectrum in Figure 11a) indicates that the microparticle is nearly fully oxidized (CeO 2 ), which is homogeneous across the island [61]. After dosing 25 kL of hydrogen at a sample temperature of 430°C, however, additional peaks are observed on the lower energy side of both the M4 and M5 edges, consistent with Ce 3+ formation [62,63]. The spectrum is still dominated by the Ce 4+ peaks, showing that the complete particle is only mildly reduced, indicating that the reduction by H 2 is a slow, activated process.…”
Section: Chemical State and Reactivitymentioning
confidence: 99%