Electronic structure and chemical bonding in nonstoichiometric zirconium nitrides

X-ray emission spectra were taken and band calculations using the Green function LMTO method and cluster calculations using the discrete variational X method were carried out for the electronic structure and chemical bonding parameters for nonstoichiometric zirconium nitrides containing metallic and metalloid vacancies. The existence of structural defects leads to a redistribution of the occupancies of the major sub-bands of the nitride valence spectrum and the formation of a new group of states between the p-d- and d-like bands of ZrN_1.0.Institute of Chemistry, Urals Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 5, pp. 82–89, September–October, 1989.     

Hierarchy of percolation thresholds and the mechanism for reduction of magnetic moments of transition metals intercalated into TiSe<Subscript>2</Subscript>

The concentration dependences of the effective magnetic moment of transition metal atoms intercalated into TiSe₂ are analyzed in the framework of the percolation theory. It is shown that, depending on the degree of localization of impurity states, the effective magnetic moment is determined by the overlap of 3d orbitals of transition metals or orbitals of titanium atoms coordinated by impurity atoms.     

The gross beta activity of surface sediment in different urban landscape areas

Journal of Radioanalytical and Nuclear Chemistry - A castable polyurethane (PUR) with soft segment made by polytetrahydrofuran polyol (or polytretramethylene ether glycol?=?PTMEG)...     

Circular dichroism of photoemission of Fe<Subscript>1/4</Subscript>TiTe<Subscript>2</Subscript>

High-resolution ARPES has been employed for examination of angular distribution of valence band photoelectrons emitted by a Fe_1/4TiTe₂ single crystal near the point Γ of the Brillouin zone in the most symmetrical directions ΓK (A-H) and ΓM (A-L) under excitation with synchrotron radiation (21.5 eV, He I) at 50 K. It has been found out that excitation with circular polarized synchrotron radiation results in essential circular dichroism in angular dependence of valence band photoemission of Fe_1/4TiTe₂. Analysis of entire experimental data has revealed that the dichroic effect is also related to the chiral geometry of the experiment. The decrease in symmetry induces dichroism, thus allowing determination of electron states at intercalant atoms.     

X-ray emission spectra and electron structure of neutron irradiated V3Si

The results of the X-ray VKβ₅ emission spectra of V₃Si irradiated with fast neutrons are reported. A comparison with the spectrum for unirradiated V₃Si as well as with cluster calculations suggested that the changes observed in the electron structure of irradiated V₃Si result from antisite defects and inhomogeneous atomic distribution.     

Structural defects and the electronic structure of zirconium hydrides: x-ray emission spectra and quantum chemical calculations

X-ray emission spectroscopy and the Green function LMTO band method was used to study the effect of structural defects in the hydrogen sublattice on the electronic structure and chemical bonding in ZrH₂.Institute of Metal Physics, Urals Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 6, pp. 70–74, November–December, 1989.     

Resonant photoemission at the L3 absorption edge of Mn and Ti and the electronic structure of 1T-Mn0.2TiSe2

Resonant valence band x-ray photoelectron spectra (ResPES) excited near the 2p(3/2) core level energies, 2p x-ray photoelectron spectra (XPS) and L(3,2) x-ray absorption spectra (XAS) of Ti and Mn in single crystals of 1T-Mn(0.2)TiSe(2) were studied for the first time. The ionic-covalent character of the bonds formed by the Mn atoms with the neighboring Se atoms in the octahedral coordination is established. From the XPS and XAS measurements compared with the results of atomic multiplet calculations of Ti and Mn L(3,2) XAS, it is found that the Ti atoms are in the ionic state of 4 + and the Mn atoms are in the state of 2 +. In ResPES of Mn(0.2)TiSe(2) excited near the Ti 2p(3/2) and Mn 2p(3/2) absorption edges the Ti 3d and Mn 3d bands at binding energies just below the Fermi level are observed. According to theoretical calculations of E(k) the Ti 3d states are localized in the vicinity of the Γ point and the Mn 3d states are localized along the direction K-Γ-M in the Brillouin zone of the crystal.     

Resonance photoelectron spectroscopy of TiX2 (X = S, Se, Te) titanium dichalcogenides

The photoelectron valence band spectra of TiS₂, TiSe₂, and TiTe₂ dichalcogenides are investigated in the Ti 2p-3d resonance regime. Resonance bands in the vicinity of the Fermi energy are found for TiS₂ and TiTe₂. The nature of these bands is analyzed based on model calculations of the density of electronic states in TiS₂, TiSe₂, and TiTe₂ compounds intercalated by titanium atoms. Analysis of experimental data and their comparison with model calculations showed that these bands have different origins. It is found that the resonance enhancement of an additional band observed in TiS₂ is explained by self-intercalation by titanium during the synthesis of this compound. The resonance enhancement in TiTe₂ is caused by occupation of the 3d band in Ti.     

The concentrations and exposure doses of radon and thoron in residences of the rural areas of Kosovo and Metohija

This paper deals with the results of indoor radon and thoron concentrations and exposure doses obtained for 63 dwellings out of the 14 rural communities of Central Kosovo, North Kosovo and Prizren region. These research activities are part of overall radiological research that has systematically been carried out since 1986, particularly in Kosovo and Metohija regions. Passive radon/thoron discriminative detectors, exposed for three months, were used. The arithmetic mean concentrations of indoor radon and thoron are C_Rn = 429 Bq m^?3 C_Tn = 85 Bq m^?3.     

The anisotropy of X-ray emission spectra for 2H-MoS2 single crystals

The angular dependence of the polarised X-ray S Kβ₁ and Mo Lβ_{2, 15} spectra of single-crystal 2H-MoS₂ has been studied. A discussion of the experimental data obtained is performed on the basis of a local symmetry analysis of atoms.