Indication of single-crystal PuO2 oxidation from O 1s x-ray absorption spectra

A. Modin, Y. Yun, M. T. Suzuki, J. Vegelius, L. Werme, J. Nordgren, P. M. Oppeneer, S. M. Butorin

研究成果: Article査読

21 被引用数 (Scopus)

抄録

The electronic structure of single-crystal PuO2 is studied using O 1s x-ray absorption (XA) and x-ray emission. Interpretation of the experimental data is supported by extensive first-principles calculations on the basis of the density functional theory+U approach. The measured XA spectra show a significant difference in intensity for the first two peaks between different spots or areas on the single crystal. Our theoretical simulations show that the first peak, at ~531 eV, can be attributed to O 2p-Pu 5f hybridization, while the second peak, at ~533.4 eV, is due to hybridization of O 2p with Pu d states. The reasons for the observed differences in the O 1s XA spectra are explored by calculating a number of defect structures PuO2±x as well as by simulating the existence of Pu(V) sites. Our results indicate the presence of oxidation states higher than Pu(IV) in some areas of the single crystal. The findings also suggest that plutonium oxide with a Pu fraction in an oxidation state higher than Pu(IV) consists of inequivalent Pu sites with Pu(IV)O 2 and Pu(V)O2 rather than representing a system where the Pu oxidation state is constantly fluctuating between Pu(IV) and Pu(V).

本文言語English
論文番号075113
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
83
7
DOI
出版ステータスPublished - 2011 2 15
外部発表はい

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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