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The equilibrium boundary for the layered VTiSesolid solution was determined according to a set of experimental data of synchrotron radiation X-ray photoelectron spectroscopy and electromotive force of the Li|Li|VTiSeelectrochemical cells. This boundary appears to be 20 mol % of V (x = 0.2). The formation of the VSestructural fragments, which are tightly bounded with VTiSelayers, appears at x > 0.2. A combined analysis of the Fermi-surface maps and the atomic force microscopy images reveals that the (001) planes in VSeand VTiSestructural fragments are parallel to each other. At the same time, these fragments demonstrate turbostratic disordering within the basal plane. The formation of such pseudo-homogeneous materials is associated with the contribution of the free surface energy, which is relatively high in the quasi-two-dimensional materials.

The effect of atomic ordering in the cobalt sublattice on the electronic structure of the CoxTiSe2 intercalation compounds has been studied using a complex of spectral techniques – XPS, XAS, and ResPES, along with theoretical calculations of the total and partial densities of states. It has been found that the cobalt intercalation significantly affects the character of the chemical bond inside the host lattice. No signs of the direct overlapping of the Co 3d orbitals in the ordered material were observed. It has been found that the reason for the ordering of the cobalt atoms is a Co 3d/Ti 3d/Se 4p hybridization.

The CuxZrSe2 intercalation single crystals have been synthesized and studied in a concentration range of x = 0-0.3, in which the semiconductor-metal transition was observed. The evolution of the electronic structure of CuxZrSe2 as a function of the copper content has been studied experimentally using the XPS and XAS methods. The obtained results indicate the gradual shift of the Fermi level with increasing copper content, which does not allow the metal-insulator transition to be associated with charge transfer to the conduction band. This transition is associated with the formation of the covalent bond between copper and the nearest selenium atoms and of the p-d hybridized states inside the Zr 4d/Se 4p band gap. First-principle calculations were performed in order to obtain a theoretical description of the density of states near the Fermi level and confirm this conclusion.

The effect of atomic ordering in the cobalt sublattice on the electronic structure of the Co

Crystal and electronic structure, optical absorption and transmission spectra, temperature dependences of conductivity and magnetic susceptibility were studied for copper intercalated ZrSe(2)in the copper concentration range of 0

The electronic structure of the NixTiSe2 intercalation compounds with disordered and ordered Ni atoms is studied using photoelectron, resonant photoelectron and X-ray absorption spectroscopy, theoretical calculations of the X-ray spectra and density of electronic states. The increase in the covalent component of the chemical bond of Ni and Ti with the nearest neighbour was found with increasing nickel concentration and its ordering. A significant charge transfer from the Ni atoms to the host lattice resulting in the transformation of Ti4+ into Ti3+ occurs, while the symmetry of the crystal lattice is lowered from the hexagonal to the monoclinic one.

Influence of the covalence, octahedral distortion and the translation symmetry of the chromium ions in octahedral coordination on the electronic structure for compounds under investigation was clarified. Cr L 2,3 and Ti L 2.3 X-ray absorption spectra (XAS) along with atomic multiplet calculations and resonant Ti 2p-3d and Cr 2p-3d photoelectron spectra of valence band (RXPS) in the intercalated titanium dichalcogenides Cr x TiX 2 (X = Se, Te) and in the substitution compound Ti x Cr 1− x Se 2 show the charge transfer between chromium and titanium sublattices.

Interaction (25–620°C) of aluminum and its alloys with an atmosphere saturated with nitrogen was studied to determine the role played by rare-earth metals in the mechanism by which nitride phases are formed in oxidation of Al + REM alloys in air. The ellipsometric method and Auger electron spectroscopy were used to determine that, under the given experimental conditions, metallic aluminum is subjected to the greatest extent to the nitridation process, which is competing with the oxidation process. The process is initiated by the conversion of the amorphous oxide film to γ-Al2O3. The surface of Al + REM alloys interacts with nitrogen at the outer part of the oxide layer. The rare-earth metal actively reacts with impurity oxygen present in the atmosphere under study and hinders formation of nitride/oxynitride layers.

The electronic structure of the ZrX

X-ray photoemission and absorption spectra of TiS3 are studied. The temperature dependence of the magnetic susceptibility is measured and the electron density of states is calculated. Titanium ions in different oxidation states are found to coexist.

An experimental study of the electronic structure of V

The electronic structure of the Ni

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.

An experimental study of the electronic structure of copper intercalated titanium dichalcogenides in a wide range of copper concentrations (x = 0.05 - 0.6) using the x-rays photoemission spectroscopy, resonant photoemission and x-rays absorption spectroscopy has been performed. Negative energy shifts of the Ti 2p and Se 3d core levels spectra and a corresponding decrease of the photon energy in Ti 2p absorption spectra with increasing concentration of copper have been found. Such sign-anomalous shifts may be explained by the shielding effect of the corresponding atomic shells as a result of the dynamic charge transfer during the formation of a covalent chemical bond between the copper atoms and the TiSe2 matrix., Comment: 12 pages, 6 figures

Single crystals of the Cu xTiSe 2 compound with x = 0.05, 0.09, and 0.33 have been grown. Resonance photoelectron Cu 3p-3d and 2d-3d spectra of the valence bands, the spectra of the core levels, and the L absorption spectra for titanium and copper have been obtained. It is shown that the degree of oxidation of titanium atoms is +4 and the state of copper atoms is close to the state of free copper ions. It is found that the spectra of the valence bands obtained under the Cu 3p and 2p resonance conditions radically differ. For the spectra in the Cu 2p excitation regime, several bands corresponding to different decay channels of the excited state are observed. According to calculations of the density of states, the 3d states of copper are filled incompletely; the occupancy of the 3d band of copper is 9.5 electrons per atom. © Pleiades Publishing, Inc., 2012.

The electronic structure and the chemical bond in titanium dichalcogenides TiX2 (X = S, Se, Te), which are promising electrode materials for lithium batteries, are studied experimentally and theoretically. It is found that the X-ray photoelectron spectra of the valence bands and the core levels of titanium and its X-ray L 2, 3 absorption spectra demonstrate a change in the ionic and covalent components of the chemical bond in these compounds. The densities of states in these compounds are calculated by the full-potential augmented-plane-wave method, and multiplet calculations of the X-ray L 2, 3 absorption spectra of titanium are performed. It is shown that, in the row TiS2-TiSe2-TiTe2, the covalence increases, the ionicity of the chemical bond decreases, and the effect of the crystal field of a ligand is weakened.

Solid solutions of 1T-CrxTi1−xSe2 (x = 0−0.83) were synthesized for the first time. To study the electronic structure of CrxTi1−xSe2 monocrystals, photoemission spectra of core levels, resonance spectra of valence bands, and absorption spectra of Ti and Cr were obtained. Titanium and chromium atoms were found to have the oxidation state 4+ and 3+, which is supported by atomic multiplet calculations for Ti and Cr in the octahedral environment. According to calculation of the local density of chromium electronic states, the Cr3d electrons are spin-polarized, and the density of chromium states is of half-metal nature. The calculation agrees well with the experimental data.

CrxTi1 − xSe2 (x = 0–0.83) solid solutions have been synthesized. Single crystals have been grown in the range of concentrations x = 0–0.83. Structural studies of samples have revealed that chromium atoms substitute titanium in the TiSe2 matrix. The X-ray photoelectron spectra of the core levels, the resonance spectra of the valence bands in 1T-CrxTi1 − xSe2, and the X-ray absorption spectra of titanium and chromium are studied. The titanium and chromium atoms are shown to have oxidation numbers of +4 and +3, respectively, in an identical octahedral environment. The local density of chromium states has been calculated. The results of the calculation agree well with the experimental data and indicate that the electronic 3d states of chromium substituting titanium in the matrix are spin-polarized and the density of chromium states is halfmetal magnet in behavior.

We synthesize Cr x Ti 1− x Se 2 ( x = 0–0.83) and Cr x Ti 1− x S 2 ( x = 0.3–0.4) systems and study the structure of these materials on mono- and polycrystalline samples. It appeared that an increase in chromium content leads to inversion of titanium diselenide intercalated with chromium to chromium diselenide intercalated with titanium. The XPS of core levels and valence bands of 1T-Cr x Ti 1− x Se 2 and Cr x Ti 1− x S 2 was also investigated and it was shown that in in-layer and inter-layer positions the atoms of chromium and titanium are characterized by a slightly differing oxidation state. Chromium LDOS model calculations were carried out and the results being in agreement with the experimental data show that the Cr 3d density of electronic states of chromium in Ti-positions in the host lattice displays half-metallic properties, while the Cr 3d density of electronic states of intercalated chromium is far from being half-metallic.

We have investigated the charge transfer characteristics and electronic structure of ferrocene-intercalated TiSe2. The spectroscopic results revealed that an intercalation of metallocene molecules leads to changes in the ionic valence of Fe atom in ferrocene molecule and the band gap, which is in accordance with electrical resistivity measurements showing metallic conductivity. Our analysis of 57 Fe Mossbauer and Fe 2p XAS spectra suggested that the suppression of charge-density-wave state in TiSe2 and an appearance of metallic conductivity are attributed to charge transfer of electrons from ferrocene intercalant to the dichalcogenide host material. 2010 Published by Elsevier B.V.

The electronic structure of the ZrX2 (X = Se, Te) compounds has been studied using photoelectron, resonant photoelectron and X-ray absorption spectroscopy, theoretical calculations of the X-ray absorption spectra, and density of electronic states. It was found that the absorption spectra and valence band spectra are influenced by the chalcogen type. The results of the multiplet calculation of the Zr4+ atom show that the change in the splitting in the crystal field, which is described by the 10Dq parameter, is due to the change in the ratio of covalent and ionic contributions to the chemical bond. The resonance band near the Fermi level in the valence band spectra is observed for ZrTe2 in the Zr 3p-4d resonant excitation mode. The extent of photon energy indicates the charge localization on the Zr atom. Similar resonance band for ZrSe2 is absent; it indicates the presence of a gap at the Fermi level. © 2018 Author(s).

This paper reports on the results of the experimental investigation into the angular dependence of the photoemission of the valence band (the angle-resolved photoelectron spectrum) for the Fe1/4TiTe2 single crystal upon excitation with circularly polarized radiation. The angle-resolved photoelectron spectrum is studied in the vicinity of the Γ point of the Brillouin zone in the two directions ΓK and ΓM with the highest symmetry. The measurements are performed in noncoplanar geometry. The circular dichroism in the photoemission angular distribution is observed over the entire ranges of energies and angles. The magnitude of the dichroism depends on the choice of the band, the binding energy, and the polar angle and varies from 0 at the Γ point to 20%.

The L 2, 3 spectra of titanium in the layered compound TiSe 2 and intercalated compounds Fe 1/2 TiSe 2 , Cr 1/3 TiSe 2 , and Fe 1/4 TiTe 2 are studied. Theoretical calculations of the electronic structure of these compounds are performed. The experimental data and calculations suggest that the intercalation of the Cr and Fe atoms into the TiSe 2 matrix brings about a partial filling of the Ti 3 d states and the spin polarization of the Cr 3 d and Fe 3 d states. Chemical bonds are formed through the hybridization of the d orbitals of intercalated atoms with the Ti 3 d -Se 4 p states of the matrix.

The 3d metal resonant X-ray emission spectra (RXES) and L3,2 X-ray absorption spectra (XAS) of the Co2MnZ (Z=Al, Ga, Sn, Sb) alloys were measured using linearly polarized soft X-rays. The Mn and ...

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 Mn X-ray emission spectra and X-ray photoelectron spectra of Mn-based Heusler alloys Co 2 MnAl, Co 2 MnSb and La 1− x Sm x Mn 2 Si 2 rare-earth compounds ( x =0, 0.8) have been measured and discussed in connection with a value of the local magnetic moment at Mn site. The spectra peculiarities reflect also the localization degree of 3d valence electrons of 3d metals in the considered compounds and could be used as an indicator of the closeness of the density of states to half-metallic character.

Results of X-ray fluorescence measurements of MA 2 Ca n-1 Cu n O 2n + 3 compounds with [ M -12(n-1)n] type structures, ( C 0.8 N 0.2 Sr 2 CuO 5.3, [ Cu 0.25 (C,N) 0.75] Sr 2 CaCu 2 O y, Cu 0.5 V 0.5 Sr 2 CaCu 2 O 7.5, Cu 0.5 V 0.5 Sr 2 Ca 2 Cu 3 O 9.4, Cu 0.5 V 0.5 Sr 2( Ca 3.6 Sr 0.4) Cu 5 O 13.5 and Cu 0.5 V 0.5 Sr 2( Ca 4.7 Sr 0.3) Cu 6 O 15.3, are presented. The experiments show that C-atoms form a distorted CO 3 oxyacid group with a partial substitution of copper and nitrogen atoms in the M-sites. We conclude that the CO 32- group in (C,N) Sr 2 Ca n-1 Cu n O y and (Cu,C,N) Sr 2 Ca n-1 Cu n O y is substituted by the NO 2- which induces the creation of the hole carriers in these compounds. We have found that V-atoms in the given compounds form ( VO 4)3- tetrahedrons and have a pentavalent state.

An experimental study of the electronic structure of VxTi1-xSe2 system in a wide range of vanadium concentrations (x = 0.06-0.9) using x-ray photoelectron spectroscopy and resonant photoelectron spectroscopy has been performed. The partial charge transfer from the VSe2 to TiSe2 structural fragments is experimentally observed, and the most part of the charge is localized on the vanadium atoms in the VSe2 structural fragments.

The ground-state structures of Ti dichalcogenides are optimized from first principles using the full-potential linearized augmented-plane-wave method. The electronic structure and magnetization in several M 1/3 TiSe 2 and M 1/3 TiTe 2 ( M = Cr, Mn, Fe) systems are studied in the supercell approach. Calculated exchange splitting of Cr2p 3/2 core level in Cr 1/3 TiSe 2 agrees well with that observed by X-ray photoelectron spectroscopy; calculated local magnetic moments are consistent with the magnetic susceptibility data. An evidence is given in favour of localized polaron-type states being created in M x TiSe 2 systems, that accounts for an observed correlation between structure distortion, magnetic moments, and electrical conductivity data.

In this article we present a detailed study of the electronic structure from various Mn-based Heusler alloys using x-ray photoelectron spectroscopy (XPS) and x-ray emission spectroscopy (XES) techniques. Performing the measurements on the Mn-$2p$ core levels as well as on the valence-band states we arrive at a more or less complete description of the electronic and magnetic properties of these compounds. The experimental Mn-$2p$ spectra have been compared with fully relativistic photoemission calculations, which are based on the solution of the spin-polarized Dirac equation. The almost constant exchange splitting of about 0.35 eV, measured between the different Mn-$2p$ sublevels is explainable in terms of the local magnetic moment at the Mn site. Moreover a strong relationship between the magnetization direction and the line shapes of the calculated Mn-$2p$ core-level spectra has been revealed from our analysis. Depending on the atomic number of the Z element we obtain from XES experiments an increasing localization of the Mn-$3d$ states. Also the interatomic distances in the different alloys seem to play an important rule in this process. To support this result we performed in addition valence-band measurements by applying XP. These data, which agree very well with the corresponding x-ray emission spectra are quantitatively reproduced from first-principle electronic structure calculations.

The band properties of the quasi two-dimensional transition metal sulphide alloy system BaCo 1 − x Ni x S 2 ( x =0, 0.1, 0.2, 0.5, 1.0) have been studied by X-ray photoelectron, X-ray absorption and X-ray fluorescence spectroscopy with tunable synchrotron radiation. It is found that the metallic character of the BaCo 1 − x Ni x S 2 system increases with x in accordance with the results of transport property measurements. The S L 2,3 X-ray emission spectra show an excitation energy dependence which allowed separate mapping of the distribution of S(2) and S(1)+S(2) 3s3d partial density of states.

A VO2 single-crystal has been subject of a combined investigation by high resolution XPS, x-ray emission spectroscopy with electron and energy-selective x-ray excitation (V L-alpha, V K-beta-5- and O K-alpha emission) and x-ray absorption spectroscopy (O1s). We performed first principles tight-binding LMTO band structure calculations of VO2 in both monoclinic and tetragonal rutile structures and compare the densities of states with the experimental data. From this we conclude that the electronic structure of VO2 is more bandlike than correlated.

measurements of S L 2,3 ultra-soft X-ray emission spectra excited by synchrotron radiation at hv=163-165 eV for samples with 240 ppm S in Ni after annealing at 400-700°C are presented. It is found that S L 2 X-ray emission spectra of S-impurity atoms in Ni show fine structure which can be simulated by a superposition of spectra of nickel sulphide and pure sulphur providing evidence that sulphur atoms are present after annealing both in solid solution and in clusters where they form S-S bonds. The variation of temperature and time of annealing (at T=400°C for I h and at T=700°C for 2 h) leads to some redistribution of intensity of S L 2 3 X-ray emission valence spectra which can be attributed to changes in the number of S-Ni and S-S bonds in accordance with the limit of sulphur solubility at these temperatures.

The possibility of substituting S 2− and SO 4 2− ions into the superconducting cuprate, La 1.85 Sr 0.15 CuO 4 ( T c ≈ 40 K) has been investigated. In contradiction to previous reports, no evidence has been found for the successful incorporation of S 2− into this material, but SO 4 2− groups show limited solubility, and are situated at the copper sites. A change in the cell symmetry from tetragonal to orthorhombic occurs at a substitution level of between 5% and 10%. The presence of sulphur in the form of SO 4 2− groups has been confirmed by X-ray emission spectroscopy for samples prepared from both sulphides and sulphates. Structure refinements based on X-ray powder diffraction data indicate that the SO 4 2− groups are substituting at the copper sites. SQUID measurements have also been performed and show that superconducting properties are adversely affected as the level of substitution is increased.

A full study of the electronic structure of 4d and 5d silicides (RuSi, RhSi, PdSi, OsSi, IrSi, , PtSi) is undertaken including XPS VB and XES ( and ) measurements and LMTO band structure calculations. It is found that d bands which dominate the density of states are more localized with increasing atomic number Z of the transition metal. A strong hybridization between silicon 3p and transition metal d states occurs over the entire valence band. Si 3s states are found to be not mixed with Si 3p and nd states but Si 3d states participate in bonding and hybridize with transition metal d states. The non-bonding character of the majority of nd states is not confirmed for 4d and 5d silicides.

The results of ab initio band-structure calculations and measurements of x-ray-emission valence spectra (XES) (Cu L\ensuremath{\alpha}, V K${\mathrm{\ensuremath{\beta}}}_{5}$, V L\ensuremath{\alpha}, S K${\mathrm{\ensuremath{\beta}}}_{1,3}$, S ${\mathit{L}}_{2,3}$) and x-ray-photoelectron valence-band and core-level spectra (XPS) of ${\mathrm{CuV}}_{2}$${\mathrm{S}}_{4}$ thiospinel are presented. It is found that a peak in valence-conduction bands close to Fermi level is formed by V 3d states, which provide the metallic properties of ${\mathrm{CuV}}_{2}$${\mathrm{S}}_{4}$. The valence band is formed by Cu 3d, V 3d, V 4p, and S 3p states. Examination of the XES and XPS results and the calculated charge-density maps and densities of states indicates that the valences of both Cu and V are similar to those of their elemental solids. Calculations show a strong electron-phonon coupling in ${\mathrm{CuV}}_{2}$${\mathrm{S}}_{4}$ and the prospect of superconducting behavior has not been confirmed. \textcopyright{} 1996 The American Physical Society.

The electronic band structures of 1T-TiTe2 and Fe0.25TiTe2 have been clarified by angle-resolved resonant-photoemission spectroscopy. Upon Fe intercalation, while most of the band structure is unchanged, two new flat bands appear at the Fermi level and at E∼−0.5 eV. Constant-initial-state spectra indicate that these states are derived from both Ti 3d and Fe 3d states. While the Fermi wave number of the electron pocket around M point is reduced by Fe intercalation, those of hole pockets around Γ point are almost unchanged, suggesting that the additional electrons are accommodated by the new flat band at −0.5 eV.

The full set of high-energy spectroscopy measurements including X-ray photoelectron valence band spectra and soft X-ray emission valence band spectra of both components of FeSi (Fe K_beta_5, Fe L_alpha, Si K_beta_1,3 and Si L_2,3) are performed and compared with the results of ab-initio band structure calculations using the linearized muffin-tin orbital method and linearized augmented plane wave method., 11 pages + 3 PostScript figures, RevTex3.0, to be published in J.Phys.:Cond.Matter

The influence of polaron concentration on the type of transition from band to activate conductivity has been investigated. For a single polaron in the crystal lattice or for material with polaron concentration higher than the percolation threshold, such a transition is continuous, in accordance with theory. However, for intermediate cases this process becomes step-like, because the rapid increase of density of states at Fermi level leads to a change of polaron characteristics. These suppositions are illustrated by experimental results (XPS-spectra, crystal structure analysis, DC conductivity) for intercalation compounds based on titanium dichalcogenides.

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 0.2TiSe 2 were studied for the first time. The ioniccovalent 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 0.2TiSe 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 point and the Mn 3d states are localized along the direction KM in the Brillouin zone of the crystal. © 2012 IOP Publishing Ltd.

The X-ray emission lines S K beta (3p to 1s) and S L2,3 (3s to 2p) have been measured for the misfit layer compounds (BiS)1.08NbS2 and (PbS)1.14TaS2 and the corresponding binary sulphides Bi2S3, NbS2, PbS and TaS2. The X-ray emission data are compared with X-ray photoelectron spectra and band structure calculations of isolated model layers. The experimental data show very clearly the character of the different valence band states, and partial density of states schemes are easily deduced from these data. A comparison with band structure calculations shows a good agreement with the measured spectra.

X-ray emission Kα 1,2 and Kβ 1 spectra of sulphur and phosphorus in [Y 0.89 Sr 0.11 ]Sr 2 Cu 2.78 (SO 4 ) 0.22 O 6.12 and YSr 2 Cu 2.79 (PO 4 ) 0.21 O 6.16 have been investigated. According to an analysis of their fine structure and energy position it is confirmed that the S and P atoms indeed enter superconducting cuprates in the form of oxyanions. It is also found that in YSr 2 Cu 3 O 7−δ containing sulphate groups 0.2 vol.% of CuS is present as an additional phase.

Electronic structure and chemical bonding in TiX2 (X=S, Se, Te), TMxTiSe2 (TM=Cr, Mn, Cu) and CrxTi1-xSe2 were studied by x-ray resonance photoemission and absorption spectroscopy. These methods are detected to be strong sensitive to chemical bonding. Charge transfer from the intercalated atoms to Ti 3d band is detected. Narrow Ti 3d and Cu 3d bands are observed under Fermi level in CuxTiSe2., Comment: 7 pages, 4 figeres, ISIC 16 conference

The analysis of substitution effects upon doping of YBa 2 Cu 3 O 6+x S y by sulphur is given on the basis of investigation of SKα 1,2 and SKs 1 x-ray emission spectra. It is found that sulphur can enter the lattice of YBa 2 Cu 3 O 7 and substitute oxygen atoms. With increasing sulphur concentration from y>0.5 to 2.0 S atoms form isolated sulphate groups which do not have a long order but can be detected by x-ray emission spectroscopy.

The results of an investigation of Fe-implanted (E = 40 keV, D = 1016 cm-2) silicon crystal by the use of soft X-ray emission spectroscopy with a variation of the exciting electron energy are presented. Based on the study of X-ray SiL2,3, Fe Lα and Si Kα spectra obtained at various exciting electron energies, the concentration profile as a function of the depth is constructed. The thickness of a buried FeSi-FeSi2 layer is estimated to be about 2000 A.

The analysis of substitution effects upon doping of YBa2Cu3O6+xSy by sulphur is given on the basis of the investigation of S Kα1,2 and S Kβ1 X-ray emission spectra. It is found that sulphur can enter the lattice of YBa2Cu3O7 and substitute oxygen atoms. With increasing sulphur concentration from y > 0.5 to 2.0 S atoms form isolated sulphate groups which do not have a long order but can be detected by X-ray emission spectroscopy.

X-ray emission spectra were taken and band calculations using the Green function LMTO method and cluster calculations using the discrete variational Xα 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 ZrN1.0.

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.