A. Yu. Teterin

The XPS spectra of cerium compounds containing oxygen

Abstract The fine structure of XPS lines of electrons of valent and inner subshells in cerium oxide CeO2, orthoniobate CeNbO4, ortomethoxibenzoateCeL3(L = C6H4OCH3COOH−) and diphenylacetateCeL′3·2H2O(L′ = (C6H5)2CHCOO−) was studied in the range of electron binding energies from 0 up to 1350 eV. Its comparison with trifiuoride CeF was carried out in order to determine the mechanism of such structure occurrence and the oxidation degree of cerium ions in the compounds. It was established that the structure Ce(II) has more in common with the studied compounds and differs essentially from that of the Ce(IV) in cerium oxide CeO2. It allows one to determine the oxidation degree of the cerium in the compounds on the basis of the values of the XPS line parameters. On the basis of experimental data it was supposed that the structure, for example of the Ce3d-electron spectrum in CeO2, is connected with final electronic states of cerium ion: Ce3d94f0, Ce3d94f1VMO−1 and Ce3d95s1(5p5)4f0ns(np). It is worth noting that the unique final state formally designated as Ce3d95s1(5p5)4f0ns(np) is not the state with the additional hole on the atomic Ce5s(5p) orbital, but that of on inner valent molecular orbital of a1g (t1u) type for the cluster CeO812− of Oh symmetry group, generally consisting of Ce5s(5p), O2s and O2p atomic orbitals of neighbouring Ce and O atoms in CeO2.

Auger and X-ray photoelectron spectroscopy study of the density of oxygen states in bismuth, aluminium, silicon and uranium oxides

The correlation of relative partial electron density at the oxygen ions with the intensity of Auger O KLL lines in Bi2O3, Al2O3, SiO2 and UO2 has been determined by Auger and X-ray photoelectron spectroscopic methods. The dependence of the relative intensities of Auger O KL2-3L2-3 and O KL1L2-3-lines was characterized from the binding energy of O 1s electrons. The electron density of the outer valence levels of oxygen increases as the relative intensities of Anger OKL2-3L2-3 and O KL1L2-3-lines increase. The fine structure observed in the O KL1L2-3 Auger and the O 2s XPS spectra has been explained by the formation of inner valence molecular orbitals (IVMO) from the interaction of electrons of the O 2s and filled metal ns shells.

Interaction of neptunyl with goethite (α-FeOOH), maghemite (γ-Fe2O3), and hematite (α-Fe2O3) in water as probed by X-ray photoelectron spectroscopy

The sorption behavior is studied and the physicochemical neptunium species existing on the surface of goethite (α-FeOOH), maghemite (γ-Fe2O3), and hematite (α-Fe2O3) are determined. Solvent extraction and X-ray photoelectron spectroscopy (XPS) are used to determine the neptunium surface species. The ion and elemental composition of the surface of the minerals and surface neptunyl NpO2+ complexes is determined using these data. Compounds containing neptunium(IV) or neptunium(VI) ions do not appear; rather, neptunyl (Np(V)O2+ group is complexed with surface hydroxide groups of α-FeOOH, γ-Fe2O3, and α-Fe2O3. Presumably, the oxygen atoms of iron oxides and water and/or carbonate (CO32-) or nitrate (NO3-) group lie in the equatorial plane of the neptunyl (NpO2+) group.

Inner valence molecular orbitals and structure of the X-ray O4,5(Th,U) emission spectra in thorium and uranium oxides

In the present work, the possibility of an influence of the chemical environment on the structure of O4,5(Th,U) emission spectra of thorium and uranium oxides was studied. It is noted that the fine structure in such spectra is caused by the formation of inner valence molecular orbitals, involving relatively deep Th(U) 6p and O(F) 2s atomic orbitals of the neighbouring atoms. This leads to differences between the O4,5(Th,U) emission spectra of ThO2, ThF4, UO2 and γ-UO3. Also, a comparison between X-ray photoelectron spectroscopy and X-ray emission spectroscopy data was made for the studied compounds. This allowed us to conclude that they are in good agreement.

X-ray photoelectron study of Te-W-O and Te-W-La-O glasses

AbstractThe elemental and ionic surface compositions of (TeO2)0.8 (WO3)0.2 and (TeO2)0.7(WO3)0.2(La2O3)0.1 glasses annealed at different temperatures and bombarded with Ar+ ions for various lengths of time have been determined using x-ray photoelectron spectroscopy. The results indicate that the surface layer of the glasses contains tellurium ions in two chemical states, which differ markedly in concentration. The oxidation state of one type of tellurium ion is close to that in TeO,

X-ray photoelectron study of lanthanide borosilicate glass

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The role of the U6p,5f electrons in chemical bonding of uranyl and uranium fluorides: X-ray photoelectron and X-ray emission studies

(Te 3d5/2)= 574.0 eV, and the oxidation state of the other is close to that in TeO2 [