Nuclear Technology & Radiation Protection Journal


NT & RP Journal	THE NATURE OF CHEMICAL BOND IN TRIOXIDE g-UO₃
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Vol. XVII, No. 1-2, Pp. 1-82 December 2002 UDC 621.039+614.876:504.06 YU ISSN 1451-3994 ....Back to Contents	Pages: 3-12 Authors: Yuri A. Teterin, Mikhail V. Ryzhkov, Anton Yu. Teterin, Alexander D. Panov, Anton S. Nikitin, Kirill E. Ivanov, Igor O. Utkin Abstract Low-energy X-ray photoelectron and conversion electron spectra from uranium trioxide were measured, and calculations were done for the [UO₂O₄]^6-(D_4h) cluster which reflects the structure of uranium close environment in g-UO3 in the non-relativistic and relativistic Xa-DVM approximation. This enabled a satisfactory qualitative and in some cases quantitative agreement between the experimental and theoretical data, and interpretation of such spectra. Despite the traditional opinion that before participation in the chemical binding, the U5f electrons could be promoted to the higher (for example - U6d) levels, it was theoretically proved and experimentally confirmed that the U5f electrons (about two U5f electrons) are able to participate directly in the chemical bond formation in uranium trioxide. The filled U5f states proved to be localized in the outer valence molecular orbitals energy range 4 eV - 9 eV, while the vacant U5f states were generally localized in the low-energy range (0 - 6 eV above zero). It was experimentally shown that U6p electrons not only participate effectively in the inner valence molecular orbital formation but also participate strongly (more than 1 U6p electron) in the formation of the filled outer valence molecular orbitals. Key words: XPS, Xa-DVM, uranium oxide, uranyl group, outer valence (OVMO) and inner valence (IVMO) molecular orbitals FULL PAPER IN PDF FORMAT (4.06 MB)
Vinča Institute of Nuclear Sciences :: Designed by milas :: July 2007 Last updated on September, 2010

Pages: 3-12

Authors: Yuri A. Teterin, Mikhail V. Ryzhkov, Anton Yu. Teterin, Alexander D. Panov, Anton S. Nikitin, Kirill E. Ivanov, Igor O. Utkin

Abstract

Low-energy X-ray photoelectron and conversion electron spectra from uranium trioxide were measured, and calculations were done for the [UO₂O₄]^6-(D_4h) cluster which reflects the structure of uranium close environment in g-UO3 in the non-relativistic and relativistic Xa-DVM approximation. This enabled a satisfactory qualitative and in some cases quantitative agreement between the experimental and theoretical data, and interpretation of such spectra. Despite the traditional opinion that before participation in the chemical binding, the U5f electrons could be promoted to the higher (for example - U6d) levels, it was theoretically proved and experimentally confirmed that the U5f electrons (about two U5f electrons) are able to participate directly in the chemical bond formation in uranium trioxide. The filled U5f states proved to be localized in the outer valence molecular orbitals energy range 4 eV - 9 eV, while the vacant U5f states were generally localized in the low-energy range (0 - 6 eV above zero). It was experimentally shown that U6p electrons not only participate effectively in the inner valence molecular orbital formation but also participate strongly (more than 1 U6p electron) in the formation of the filled outer valence molecular orbitals.

Key words: XPS, Xa-DVM, uranium oxide, uranyl group, outer valence (OVMO) and inner valence (IVMO) molecular orbitals

FULL PAPER IN PDF FORMAT (4.06 MB)