EXAFS and XANES studies of americium dioxide with fluorite structure

Nishi, Tsuyoshi; Nakada, Masami; Itoh, Akinori; Suzuki, Chikashi; Hirata, Masaru; Akabori, Mitsuo

doi:10.1016/j.jnucmat.2007.09.001

Cited by 23 publications

(20 citation statements)

References 17 publications

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“…EXAFS analysis was performed in view of the effect of the main multiple scattering using the atomic distances and coordination numbers of Am 2 O 3 and AmO 2 that were calculated with crystallographic data obtained from X-ray diffraction analysis (refer to Table 1). The resultants k 3 -weighted EXAFS oscillations of Am 2 O 3 and AmO 2 [12] are provided in Fig. 3, where the broken line corresponds to the calculated data in fitting it to the experimental data.…”

Section: Xanes Analysesmentioning

confidence: 99%

Local and electronic structure of Am2O3 and AmO2 with XAFS spectroscopy

Nishi

Nakada

Suzuki

et al. 2010

Journal of Nuclear Materials

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Section: Xanes Analysesmentioning

confidence: 99%

Local and electronic structure of Am2O3 and AmO2 with XAFS spectroscopy

Nishi

Nakada

Suzuki

et al. 2010

Journal of Nuclear Materials

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“…The experimental spectrum of Am L III XANES of AmO 2 22 is shown in Figure 1. There are two peaks (Peaks A and B) in this XANES.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, in this study, we estimate the local structure of Pr 6 O 11 by using the same cluster model of Pr 6 O 11 as those of AmO 2 and UO 2 for simplicity. Bond length of [AmO 8 ] 12‐ is 2.329 Å 22 and that of [PrO 8 ] 12‐ is 2.369 Å which are taken from the result of XRD measurement of these sample, and that of [UO 8 ] 12− is 2.369 Å which are taken from the literature 24. The cluster was embedded in an external field composed of point charge of +4 and −2 at the lattice sites of Am, Pr, or U and O, respectively, which produces a Madelung potential.…”

Section: Calculationmentioning

confidence: 99%

“…In our previous article, Am L III edge XANES of AmO 2 was measured and assigned well using the DV‐Xα method 22. In this article, to investigate the relation between the electronic structure and Am L III edge XANES of AmO 2 , we calculated XANES and the electronic structure of AmO 2 with the relativistic DV‐Xα method and analyzed it in detail.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of the electronic structure of AmO₂ and Pr₆O₁₁ for XANES analysis with redox property

Suzuki

Nishi

Nakada

et al. 2009

Int J of Quantum Chemistry

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ABSTRACT:We calculated X-ray absorption near-edge structure (XANES) of Am L III of AmO 2 and Pr L III of Pr 6 O 11 using the relativistic discrete-variational (DV)-X␣ method based on the Dirac-Slater method, and compared it with the experimental spectra. These spectra were calculated on a model of ). In spite of using small cluster models, the calculated spectra were in good agreement with the experiment ones. Besides, we calculated the electronic structure of AmO 2 and Pr 6 O 11 to analyze the peak structures of XANES. From this calculation, it was found that O s, p, and f components had influence on the specific peak structures but that O d component had influence on various peak structures for AmO 2 and Pr 6 O 11 . From this result, it was suggested that the change of the electronic structure of actinide 6d and O d or f was important for actinide L III XANES corresponding to oxygen to metal ratio in the oxide nuclear fuel. On the basis of these results, we calculated the fine structures of densities of states and the transition energy from the HOMO to the white line of AmO 2 , UO 2 , and Pr 6 O 11 and investigated redox properties of Am and U in the oxide nuclear fuel with the evaluation of validity of Pr as simulant materials of Am.

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“…Thus, it is a useful technique for analyzing the geometric and electronic characteristics of actinide compounds, particularly by probing the deep L III core electrons (e.g. Am x O y as in ). This technique is ideal for determining whether interstitial O atoms can be identified and characterized within a single crystal ThO 2 matrix.…”

Section: Introductionmentioning

confidence: 99%

Analysis of oxygen shell splitting in hydrothermally grown single crystal ThO₂(200)

Kelly

Petrosky

McClory

et al. 2015

Physica Rapid Research Ltrs

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Single crystals of ThO2 have been synthesized using hydrothermal growth and studied using the X‐ray absorption fine structure (XAFS) technique. The extended X‐ray absorption fine structure (EXAFS) has been extracted from the XAFS and analyzed using a novel, computational Latin hypercube sampling method. The methodology not only confirms the expected space group and crystal structure, it also identifies the origin of a previously reported split O shell. Since EXAFS is a local order analysis technique, the O shell splitting is identified as an O atom occupying an interstitial site. This result is significant for examining O2– transport in a ThO2 matrix and corroborating research indicating partial Th 5f occupancy that is similar to hyper‐stoichiometric UO2+x compounds. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

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EXAFS and XANES studies of americium dioxide with fluorite structure

Cited by 23 publications

References 17 publications

Local and electronic structure of Am2O3 and AmO2 with XAFS spectroscopy

Local and electronic structure of Am2O3 and AmO2 with XAFS spectroscopy

Calculation of the electronic structure of AmO₂ and Pr₆O₁₁ for XANES analysis with redox property

Analysis of oxygen shell splitting in hydrothermally grown single crystal ThO₂(200)

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EXAFS and XANES studies of americium dioxide with fluorite structure

Cited by 23 publications

References 17 publications

Local and electronic structure of Am2O3 and AmO2 with XAFS spectroscopy

Local and electronic structure of Am2O3 and AmO2 with XAFS spectroscopy

Calculation of the electronic structure of AmO2 and Pr6O11 for XANES analysis with redox property

Analysis of oxygen shell splitting in hydrothermally grown single crystal ThO2(200)

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Calculation of the electronic structure of AmO₂ and Pr₆O₁₁ for XANES analysis with redox property

Analysis of oxygen shell splitting in hydrothermally grown single crystal ThO₂(200)