The origin of an elastic line in the L 3 x-ray emission spectrum of metallic manganese

A strong elastic line has been found in the L ₃ x-ray emission spectrum of metallic Mn. To unravel its physical nature, the ground-state properties of α-Mn were studied in comparison with those of 3d metals (Cr and Fe in bcc structure), as well as the properties of the L ₃ absorption final states of these three transition metals. To model the electronic structure, LSDA band-structure calculations of Cr, Mn, and Fe were carried out, and L ₃ absorption spectra of these metals were computed in the atomic approximation. A joint analysis of the properties of the ground state and of the final absorption state excited by an x-ray-produced core hole suggests that the elastic line in the α-Mn spectra should be assigned to the specific character of the absorption final-state multiplet.     

The electronic structure of NbO: Theory and experiment

Experimental photoelectric- and X-ray emission spectra obtained from NbO are compared with the molecular orbital calculations of NbO₆^10? cluster using X_α discrete variational method. The agreement between theory and experiment establishes the validity of the cluster approach to determine the electronic structure of the 4d transition metal chalcogenides.     

The effect of atomic ordering on the photoelectron spectra of V3Au

The X-ray photoelectron (XPS) spectra of the valence bands are measured on 3 different modifications of the compound V₃Au, as obtained from the same starting sample. Two of these modifications are of the same crystal structure type (A 15), but have a different LRO parameter, S. An increase of the XPS V3d density of states, in agreement with the observed increase of the electronic specific heat coefficient, γ, and the superconducting transition temperature, T_c.     

Field Electron And X-Ray Emission Spectroscopy of Submicroscopic Nickel

Samples of submicrocrystalline nickel (d = 100 nm) prepared under the action of strong plastic strains are investigated by the methods of field electron and x-ray emission spectroscopy and transmission submicroscopy. Qualitative and quantitative differences of autoelectron distributions over total energies for a submicrocrystalline metal from those for a coarse-grained metal are detected.     

Correlation effects in photoelectron spectra of high-Tc superconductive oxides: the hole-induced redistribution of Cu3d states in La2CuO4

In the transition state model using the LMTO-Green function method an investigation is performed of the changes in energy distribution of Cu3d and O2p states in the valence band of La₂CuO₄ which are caused by the presence of the photoelectron hole. It is shown that taking the hole into account leads to a sharp decrease in the density of Cu3d states on the Fermi level and to a low-energy shift of the d band edge relative to the Fermi level. The grounds for the suggestion of the purely oxygenic nature of hole carriers in high-T_c superconductors are discussed.     

Cu–CeO<Subscript>2</Subscript> nanocomposites: mechanochemical synthesis,physico-chemical properties,CO-PROX activity

Catalytic systems designated for preferential oxidation of CO in the presence of H₂ are prepared by ball milling of Cu and CeO₂, a simple and cheap one-step process to synthesize such catalysts. It is found that after 60 min of milling, a mixture of 8 wt.% Cu–CeO₂ powders exhibits CO conversion of 96% and CO selectivity of about 65% at 438 K. Two active oxygen states, which are not observed in case of pure CeO2, were detected in the nanocomposite lattice and attributed to the presence of Cu in surface sites as well as in subsurface bulk sites. Correspondingly, oxidation of CO to CO₂ was found to occur in a two-stage process with T _max ≈ 395/460 K, and oxidation of H₂ to H₂O likewise in a two-stage process with T _max ≈ 465/490 K. The milled powder consists of CeO₂ crystallites sized 8–10 nm agglomerated to somewhat larger aggregates, with Cu dispersed on the surface of the CeO₂ crystallites, and to a lesser extent present as Cu₂O.

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Plasma Flows of High-Current Discharge in a Capillary and Their Propagation Across a Magnetically Insulated Line

Russian Physics Journal - The characteristics of sources of plasma flows formed by high-current discharges in polyethylene, teflon, and ceramic capillaries are presented that allow high-velocity...