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首页> 外文期刊>Journal of structural chemistry >Resonant emission of UO_2, U_3O_8, and UO_(2+x) valence electrons under SR excitation near the O_(4,5)(U) absorption edge
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Resonant emission of UO_2, U_3O_8, and UO_(2+x) valence electrons under SR excitation near the O_(4,5)(U) absorption edge

机译：在O_（4,5）（U）吸收边附近的SR激发下UO_2，U_3O_8和UO_（2 + x）价电子的共振发射

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摘要

The structure of the resonant electron emission (REE) spectra of UO_2 (REE appears under the excitation with ynchrotron radiation near the O_(4,5)(U) absorption edge at ～100 eV and ～110 eV) is studied with regard to the X-ray _(4,5)(U) absorption spectrum of UO_2 and a quantitative scheme of molecular orbitals based on the X-ray electron spectroscopy data and the results of a relativistic calculation of the electronic structure of UO_2. The structure of the REE spectra of U_3O_8 and UO_(2+x) is studied for comparison, and the effect of the uranium chemical environment in oxides on it is found. The appearance of such a structure reflects the processes of excitation and decay involving the U5d and electrons of the outer valence MOs (OVMOs, from 0 to ～13 eV) and inner valence MOs (IVMOs, from ～13 eV to ～35 eV) of the studied oxides. It is noted that REE spectra show the partial density of states of U6 p and U5 f electrons. Based on the structure of REE spectra, it is revealed that U5 f electrons directly participate (without losing the f nature) in the chemical bonding of uranium oxides and are delocalized within CMOs (in the middle of the band), which results in the enhancement of the intensity of the REE spectra of CMO electrons during resonances. The U6 d electrons are found to be localized near the bottom of the outer valence band and are observed in the REE spectra of the studied oxides as a characteristic maximum at 10.8 eV. It is confirmed that U6 p electrons are effectively involved in the formation of IVMOs, which leads to the appearance of the structure in the region of IVMO electron energies during resonances. This structure depends on the chemical environment of uranium in the considered oxides.
机译：研究了UO_2的共振电子发射（REE）光谱的结构（REE在约100 eV和约110 eV的O_（4,5）（U）吸收边缘附近的回旋辐射激发下出现）。 UO_2的X射线_（4,5）（U）吸收光谱以及基于X射线电子光谱数据和UO_2电子结构的相对论计算结果的分子轨道定量方案。研究了U_3O_8和UO_（2 + x）的REE光谱的结构，并进行了比较，发现了铀中化学环境对氧化物的影响。这种结构的出现反映了激发和衰变过程，涉及U5d和电子的外价MOs（OVMO，从0到〜13 eV）和内价MOs（IVMO，从13eV到〜35 eV）。研究的氧化物。注意，REE光谱显示了U6p和U5f电子的状态的部分密度。根据REE光谱的结构，发现U5 f电子直接参与（不失去f性质）铀氧化物的化学键合并在CMO内部（在谱带中间）离域，从而增强共振期间CMO电子的REE光谱强度的变化。发现U6 d电子位于外价带底部附近，并在研究的氧化物的REE光谱中观察到，其特征最大值为10.8 eV。可以确定的是，U6 p电子有效地参与了IVMO的形成，这导致了共振期间IVMO电子能量区域中结构的出现。这种结构取决于所考虑的氧化物中铀的化学环境。

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