ИСТИНА

Session: AC+AS+M I-ThP2 Study of Chemical Bond in Cs2NpO2Cl4 Abstract # 1860 Author(s) Presenter Correspond Yury Teterin; NRC “Kurchatov Institute”, Russian Federation Anton Teterin; NRC “Kurchatov Institute”, Russian Federation X Kirill Ivanov; NRC “Kurchatov Institute”, Russian Federation Mikhail Ryzhkov; Ural Department of RAS, Institute of Solid State Chemistry, Russian Federation Konstantin Maslakov; Lomonosov Moscow State University, Russian Federation Stepan Kalmykov; Lomonosov Moscow State University, Russian Federation Vladimir Petrov; Lomonosov Moscow State University, Russian Federation X Dmitry Suglobov; V.G. Khlopin Radium Institute, Russian Federation Abstract: In Cs2NpO2Cl4 compound the ion of Np(VI) has an asymmetric environment of the oxygen and chlorine ions, which leads to a stronger interaction between Np6p- and O2s-electrons in the axial direction than between Np6pand Cl3s-electrons in the equatorial plane. These interactions are effectively manifested in the X-ray photoelectron spectra. Quantitative analysis was done of the valence electrons x-ray photoelectron spectra structure in the binding energy (BE) range of 0 eV to ~35 eV for dicaesium tetrachlorodioxoneptunate (Сs2NpO2Cl4) single crystal. This compound contains the neptunyl group NpO2 2+. The BEs and structure of the core electronic shells (~35 eV ‒ 1250 eV), as well as the relativistic discrete variation (RDV) calculation results for the NpO2Cl4 2- (D4h) cluster reflecting Np close environment in Сs2NpO2Cl4 were taken into account. The experimental data show that the many-body effects due to the presence of cesium and chlorine contribute to the outer (0 – ~15 eV BE) valence molecular orbitals (OVMO) spectral structure much less than to the inner (~15 – ~35 eV BE) (IVMO) one. The filled Np 5f electronic states were theoretically calculated and experimentally confirmed to present in the valence band of Сs2NpO2Cl4. It corroborates the suggestion on the direct participation of the Np 5f electrons in the chemical bond. The Np 6p atomic orbitals (AO) participate in formation of both the inner (IVMO) and the outer OVMO valence molecular orbitals (bands). The filled Np 6p and the O 2s, Cl 3s electronic shells were found to take the maximum part in the IVMO formation. The MO composition and the sequence order in the binding energy range 0 eV ‒ ~35 eV in Сs2NpO2Cl4 were established. The experimental and theoretical data allowed a quantitative MO scheme for Сs2NpO2Cl4 in the BE range0 – ~35 eV, which is fundamental for both understanding the chemical bond nature in Сs2NpO2Cl4 and the interpretation of other x-ray spectra of Сs2NpO2Cl4. The contributions to the chemical binding for the NpO2Cl4 2- cluster were evaluated to be: the OVMO contribution – 49%, the IVMO contribution – 51%. The work was supported by the RFBR grant #13-03-00214-a.