Home – Home – Jornals – Russian Geology and Geophysics 2017 number 8

Vitreous basalts and plagioclase lapilli from Tolbachik Volcano studied by high-temperature gas chromatography reveal features of a fluid regime uncommon to suprasubduction melts. Prominent depletion in volatiles confirms the anomalous behavior of the Tolbachik fluid systems. Vitreous basalts contain minor amounts of water (0.16-0.27 wt.%) and carbon dioxide (95-440 ppm). New data on volatiles in the Tolbachik plagioclase lapilli show very low contents of CO2 and total gas (exclusive of H2O) and enrichment in reduced fluids (CO and CH4) relative to the basalts. In general, analysis of basalts and plagioclase lapilli from different eruptions trace a progressive increase in reduced fluids (CO and CH4) and decrease in CO2 and total gas from past to present events. The concentrations of CO2 decrease, while those of CO and CH4 in basalts and plagioclase lapilli increase systematically with an increase in FeO/MgO ratios and K2O contents in the lavas and in anorthite component in plagioclase.

The influence of parental melts on the chemical composition of rock-forming minerals of alkaline lamprophyres (monchiquites) referred to as the volcanic series of porphyritic potassic alkaline-ultrabasic rocks was studied in the Tomtor alkaline-ultrabasic carbonatite massif (Yakutia) hosting a unique deposit of Sc-REE-Y-Nb ores. Previous fluid-melt inclusion study showed that these rocks formed from two mixing alkaline-basic melts of different alkalinity. A detailed study of the chemical composition of minerals revealed a repeated irregular zoning in most of phenocrysts, which reflects the influence of different parental magmas and their mixing. It was established that the cores of diopside phenocrysts (Di I) with inclusions of Na-Fe-rich silicate melts have a low Mg-number and low contents of Ti, Al, and Ca and high contents of Na and Mn. The intermediate zones of phenocrysts (Di II) containing inclusions of K-Mg-rich silicate melts show a high Mg-number and are rich in Ti and Al and poor in Mn and Na. Groundmass grains and rims (and, sometimes, intermediate zones) of diopside phenocrysts often have a mixed Di I-Di II composition with slightly elevated contents of Mg, Ti, and Al. Amphibole phenocrysts, like the diopside ones, have both zones with low Mg contents and high Na/K ratios and Mn contents and zones with high Mg contents, low Na/K ratios, and low Mn and elevated Ti contents. Phlogopites are also of two varieties: highly magnesian, with high contents of Si and K and low content of Mn, and lowly magnesian, with low contents of Si and K and high content of Mn. Ilmenite, titanomagnetite, and fine grains of femic minerals are mostly of mixed varying composition. The chemical composition of rock-forming minerals, especially zoned phenocrysts, evidences that they crystallized with the participation of two alkaline-basic melts: Na-Fe-rich silicate melt enriched in Mn and K-Mg-rich silicate melt enriched in Ti but depleted in Mn.

Geochemical and U-Pb geochronological studies have shown that the alkali syenites of the China massif have an age of 311.4 ± 1.8 Ma and potassic specialization in contrast to most massifs of the Vitim alkaline-magmatism zone. The rocks are similar in geochemistry to the nepheline syenites of the Synnyr massif, dated at 289.5 ± 3.5 Ma. The alkali syenites of the China massif formed, most likely, from crustal protoliths.

We study a carbonate body looking like a classical fossil travertine which was discovered in the Chebak-Balakhta basin within the Minusa Trough Basin (Khakassia, Russia) and called quasi-travertine . It is a thin layer sandwiched between a basalt-dolerite sill and calcareous siltstone. Comprehensive studies of the quasi-travertine and its comparison with Devonian fossil travertines located a few kilometers away in terms of structure and composition have made the basis for its formation model. According to this model, the quasi-travertine has had a two-stage history: deposition and subsequent hydrothermal metasomatism. Laminated limestone coexisting with calcareous siltstone of the Early Devonian Shunet Formation formed during the first stage and then experienced hydrothermal metasomatism with precipitation of secondary calcite, prehnite, and pyrobitumen (kerite).

We have analyzed the isotope-geochemical features of volcanosedimentary rocks of the Karsakpai Group in southern Ulutau (Central Kazakhstan): mafic volcanics, siliceous and siliceous-ferruginous sediments, and quartz-sericite-chlorite schists. The close association of ferruginous quartzites with intraplate volcanics indicates that they formed in a tectonically active basin. The Nd isotope composition of ferruginous quartzites was governed by synchronous underwater volcanism, whereas the 143Nd/144Nd value of schists was additionally controlled by the Nd isotope composition of older sources. The Mesoproterozoic Nd model ages and positive εNd(t) values of the metaterrigenous rocks of the Karsakpai Group indicate the presence of Mesoproterozoic juvenile material in the provenance. The minimum Nd model ages suggest the lower boundary of sedimentation of 1.3 Ga.

The cocrystallization coefficients of Cr, V, and Fe ( D _Me/Fe) in magnetite and sulfide minerals (pyrite, chalcopyrite, and Fe-containing sphalerite) in multiphase associations are determined in hydrothermal-growth experiments with internal sampling at 450 °C and 100 MPa (1 kbar). The results are compared with previous data on D _Mn/Fe. Magnetite and pyrite are characterized by the highest D _Me/Fe values for both Cr (1.2 and 2) and V (6.6 and 1.1). These minerals also show the highest mineral/solution distribution coefficients of Cr and V. For V and Cr in chalcopyrite, much lower D _Me/Fe values (0.03 and 0.04, respectively) were obtained, which, however, are slightly higher than those for Mn in magnetite (0.01). Although the deposition of magnetite and iron sulfides has no significant effect on the evolution of Mn in solution and Mn-Fe partitioning, crystallization of magnetite and pyrite favors a decrease in Cr and V contents relative to Fe content in solution. The data obtained can be used to reconstruct the chemical composition of paleofluids. Spinel minerals with close contents of Mn, V, and Cr can form through a hydrothermal process provided that the solutions are highly enriched in Mn relative to Fe and have V and Cr contents close to the Fe one. Such solutions seem to be exotic. Usually, a magnetite-forming hydrothermal fluid contains V and Cr as millionths of Fe, while the content of Mn in it can be of the same order of magnitude as the content of Fe. The data obtained may be of interest for reconstructing the evolution of the chemical composition of the World Ocean in different geologic periods. The study has shown that the bulk distribution coefficient of variable-valence elements between mineral and hydrothermal solution varies over a wide range of values even at constant pressure<M>, temperature, and solution composition and can be used only for qualitative estimation of the element compatibility. In contrast, the bulk cocrystallization coefficient of chemically similar elements is less dependent on physicochemical conditions, has a nearly three times lower variation coefficient, and permits an element partitioning analysis in heterogeneous mineral-fluid systems.

The crystal structure of betekhtinite from the Dzhezkazgan copper ore deposit, Kazakhstan, has been refined to R 1 = 0.047 for 1321 unique observed reflections. The mineral is orthorhombic, Immm , a = 3.9047 (6), b = 14.796 (2), and c = 22.731 (3) Å, and V = 1313.3 (3) Å3. The structure refinement revealed five additional partially occupied Cu sites compared to the previous structural study. The structure contains one Pb and thirteen Cu sites. The coordination of the Pb site is sevenfold. Coordination geometries of the Cu sites are variable: The Cu1, Cu2, Cu3 Cu6, Cu7, Cu8, and Cu9 sites are tetrahedrally coordinated, whereas Cu4, Cu5, Cu10, Cu11, and Cu13 have a triangular coordination. The Cu12 site is coordinated by two S atoms to form a CuS2 dumbell. The crystal structure of betekhtinite is based upon complex Pb-Cu sulfide rods running parallel to the a axis. The rods have a rhombus-like cross section with lateral dimensions of ca . 11·16 Å2. The core of the rod is composed from the CuS4 tetrahedra and may be considered a module extracted from the archetype structure of fluorite, CaF2. The tetrahedral columns are further incrustated by the Cu4S3 and Cu5S3 triangles and Pb atoms to form the [Pb2Cu16S15] rods, which are linked to each other along the b axis via S6 atoms. The low-occupied Cu sites are located in between the rods. The structural formula determined on the basis of the crystal-structure refinement can be written as Pb2Cu22.18Fe1.04S15, which is in agreement with the chemical analyses of betekhtinite and disagrees notably with the formula Pb2(Cu,Fe)21S15 suggested by Dornberger-Schiff and Höhne. The general crystal chemical formula of betekhtinite can be written as Pb2(Cu,Fe)22-24S15. Information-based structural complexity parameters for betekhtinite are: IG = 3.696 bits/atom and IG,total = 144.131 bits/cell. Decomposition of betekhtinite into a mixture of galena (PbS; IG = 1.000 bits/atom; IG,total = 2.000 bits/cell) and chalcocite (Cu2S; IG = 1.500 bits/atom; IG,total = 12.000 bits/cell) at temperatures above 150 ºC is associated with the loss of structural complexity and the rise of configurational entropy of the system.

This paper discusses the problems of selection of stratotype sections and correlation of marker beds in the Neocomian productive complex of West Siberia in the context of its clinoform structure. In this paper we present a conceptual sequence stratigraphic model and a correlation chart for beds from different lithofacies regions of the Berriasian-Lower Aptian deposits of West Siberia.

An extraordinary-thick (400 m) section of the Neogene-Quaternary deposits is for the first time exposed by well 1 in the central Uimon Basin. The Miocene-Pliocene lacustrine Tueryk Formation is recognized at the base of the continuous section, verified by new paleontological data (ostracods, spores, and pollen). As assumed, overlaying deposits are represented by the Lower Pleistocene lacustrine-alluvial Beken Formation, Middle Pleistocene alluvial-proluvial Bashkaus Formation, undifferentiated Middle Pleistocene glacial, fluvioglacial, and alluvial deposits, and Upper Pleistocene lacustrine-glacial deposits. The data obtained from the core of well 1 undisputably demonstrate that the Uimon Basin had been developed prior the beginning of the Miocene Epoch, when it was characterized by accumulation of the lacustrine Tueryk Formation, incompletely exposed within the studied section. The presence of thick unexposed lower-Ohm interval of sedimentary filling of the basin suggests that the Uimon Basin was developed as early as the Paleogene. Therefore, the tectonic evolution and sedimentation history of the basin are assumed to have features similar to those of the Chuya and Kurai Basins of Gorny Altai.

The formation and propagation of postfilamentation channels along a controllable path 150 m long are studied experimentally for collimated beams of different diameters. During multiple filamentation, a laser beam is compressed in global focus, after the passage of which its angular divergence is much greater than the divergence of postfilamentation channels generated during the filamentation. It is shown that postfilamentation channels have the intensity sufficient for the formation of multiple filamentation in optical elements after the end of the filamentation region at distances much longer than the filamentation length.

The vertical distribution of the organic component of aerosol in the boundary air layer and free atmosphere was studied on the basis of sampling from a board of Tu-134 “Optic” airborne-laboratory. The altitude range was divided into two layers: 0.5-2.0 and 3.0-7.0 km. It is shown that the aerosol organic component concentration exponentially decreases with altitude. The drop of the concentration makes 7.5 times from the surface air layer to the free troposphere. The maximal concentration in the surface air layer is observed for n-C₁₉H₄₀; in the boundary layer and free atmosphere, for n-C₁₇H₃₄. In the free troposphere, compounds heavier than n-C₂₂H₄₆ are fixed only at the trace concentration level. Redistribution of the organic component of aerosol between the surface and boundary air layers occurs during the year.

The contribution of wildfires into the content of the organic component of aerosol is studied on the basis of data of two flight campaigns carried out along the route Novosibirsk - Yakutsk - Novosibirsk in 2012 and 2013. The campaign of 2012 took place under conditions of extensive wildfires in Siberia, the campaign of 2013, on the contrary, in background conditions. The analysis of the selected aerosol samples shows that concentration of organic compounds during fires increases on the average by 35 times in the surface air layer and from 3 to 23 times in the free atmosphere in comparison with the background conditions. The composition of the organic component in the free atmosphere during fires changes depending on the region. At the Tomsk - Mirnyi segment, alkanes n-C₁₉H₄₀ - n-C₂₁H₄₄ prevailed in the aerosol samples; from Mirnyi to Yakutsk, the main concentration peak fell in the range of high-molecular compounds n-C₁₉H₄₀ - n-C₂₅H₅₂; at the Bratsk - Novosibirsk segment, low-molecular alkanes n-C₁₂H₂₆ -_{n-C18H38 prevailed in the aerosol composition.}

According to the long-term (1963-2000) observational data on depth of the Secchi Disk visibility, the main peculiarities of the annual cycle of transparency distribution in the surface water layer of the north-western Black Sea are considered. The statistical estimates of the seasonal variations in the areas differing in the degree of influence of river and open-sea water flow on their hydrophysical parameters are derived. Intra-annual transparency variations in these areas are in a good agreement with the intra-annual variations in phytoplankton biomass and water salinity. It is shown that long-term (1950-2013) intra-annual seasonal transparency variations (according to the data measured and reconstructed by means of a neural network model) show a satisfactory agreement with the intra-annual variations in the hydrobiological parameters. The dependences of the variations in these parameters on the regional meteorological conditions within El Niño - Southern Oscillation period and within the period of its absence are studied.

We describe a new algorithm for retrieving the atmospheric fine particulate matter total column (particles less than 1.0 and 2.5 μm) from multi-spectral satellite images in visible and IR regions of the electromagnetic spectrum. The algorithm is based on the regression relations between the top of atmosphere (TOA) reflectance, microphysical parameters of aerosol, and geometrical parameters of satellite scene. The regression equations are derived from the TOA reflectance calculations in the spectral channels of the satellite instrument for the ensemble of random generated parameters of the atmospheric radiative transfer model and the geometrical parameters of the satellite scene. Subsequently, this allows real-time mapping the fine particulate matter pollutions directly from the satellite images without solving ill-posed inverse problems of the solar radiation transfer in the atmosphere and aerosol light scattering. The proposed algorithm is implemented and tested for MERIS (Medium Resolution Imaging Spectrometer) satellite instrument. The comparison of the MERIS-retrieved total fine particulate matter content in the atmosphere with AERONET (Aerosol Robotic Network) data shows the standard deviation ~ 0.5 μg/cm². The application of the developed algorithm to real-time monitoring of the regional and transboundary transport of the atmospheric particulate matter pollutants during the wildfires is demonstrated.

A model of the solar radiation transfer in the Earth's atmosphere is developed for explicit calculations of the transfer characteristics of the atmosphere (reflectance, transmission, and spherical albedo) in its visible and near-IR transparency windows depending on the surface air pressure (or terrain elevation), the aerosol optical parameters, and angles indicating the position of the Sun and the satellite system with respect to the Earth's target. The model is based on the spectrally dependent approximations obtained using the atmospheric radiative transfer code DISORT. The sensitivity of underlying surface spectral albedo retrieval from top-of-atmosphere reflectance to vertical distribution of atmosphere optical parameters is investigated. The algorithm is designed for the atmospheric correction of multispectral satellite images with the developed model and applied to MERIS instrument (Medium Resolution Imaging Spectrometer). It is shown that accounting of optical properties of the atmosphere and adjacency effects in the processing of satellite images substantially improves visibility of underlining surface targets and rendering their spectral reflectance parameters

The possibilities and limitations of determining the skewness and kurtosis of sea surface slopes by spaceborne optical scanners are analysed. It is shown that these data do not allow precise retrieval of the values of skewness and kurtosis. The empirical probability density of slopes, determined according to the optical scanner data, is defined in a limited range of slopes. The Cox-Munk model used in the calculations is also defined in a limited area.

The feasibility of Levenberg-Marquardt method, modified for the case of inaccessibility of a priori covariance matrices for methane vertical profiles, for atmospheric methane total column amount retrieval from the spectra measured by IASI/METOP is studied. The method and algorithm were implemented into software package together with iterative evaluation of a posteriori covariance matrices and averaging kernels for each individual case of retrieval. This allows selection of the results on the basis of properties of both matrices. The comparison between our results and IASI standard methane products retrieved from the same spectra shows their satisfactory agreement.

The action of enhanced UV radiation at the 308 nm wavelength on the photosynthetic apparatus of Siberian spruce seedlings (Picea obovata Ledeb.) from June to August has been studied in two-year experiment. The negative effect on the photosynthetic apparatus of spruce needles is ascertained, with a pronounced cumulative effect. The suppression of the photosynthesis rate and transpiration intensity in the radiation-exposed two-year spruce needles and current-year spruce needles, primordia formed in July-September of the previous vegetation period, is shown to be deeper during the second vegetation period as compared to the first one. We revealed that the water balance of spruce needles corresponded to seasonal norms in the both groups during the experiment. The decrease of the transpiration intensity in the spruce seedlings exposed to radiation as compared to the control group is conditioned by a need in maintaining the water homeostasis in the needles. The experimental group of spruce seedlings showed a weaker correlation between the photosynthesis rate and transpiration intensity than the control group, which is clearly pronounced in the two-year needles exposed to the radiation.

We have measured the sedimentation rates of the pollen particles of several species of anemogamous plants (including those introduced by a man) growing in Western Siberia (pine trees: ordinary, Siberian, mountain, Crimean; inoculum hemp, rib grass). It is shown that upon spraying, the anemophilous pollen particles are represented by both single pollen grains and agglomerates of two or more grains. The portion of agglomerates in the total number of particles deposited is estimated. The sedimentation rates of the pollen particles are determined. The sedimentation rates of the pollen agglomerates of one or more grains are measured. The dependence of the sedimentation rate on the number of grains in an agglomerate is established.

A brief review of the results of studying some classes of nitrogen-containing chelate boron complexes by ultraviolet photoelectron spectroscopy and density functional theory is reported. The quantum chemical modeling of the substitution effects of a complexing agent, heteroatoms, and functional groups in α, β, and γ positions of the chelate ring allowed us to establish the features of the electronic structure of the studied complexes. It is found that the substitution of heteroatoms in the chelate ring has no substantial influence on the structure of the highest occupied molecular orbital (HOMO). In imidoylamidinate complexes, as opposed to formazanates and b-diketonates, there is no noticeable mixing of p orbitals of the chelate and benzene rings. In condensed nitrogen heterocycles the HOMO is stabilized by 0.2-0.3 eV and p orbitals of the benzene ring are stabilized by 0.8-1.2 eV. The HOMO of substituted aza-boron-dipyridomethene correlates with anthracene and acridine p₇ orbitals, which causes the fine structure of the first band. It is shown that in an energy range below 11 eV the calculated results reproduce well the energy gaps between the ionization states of the complexes.

The infrared spectra of the complexes of boron difluoride acetylacetonate and its halogen-substituted derivatives F₂B(aaX) (X = H, Cl, Br, I) in the crystalline state are studied. The substituent effect on the geometry and force field of molecules is revealed from DFT/B3LYP quantum chemical calculations with the 6-311G( d , p ) basis set. The detailed assignment of IR absorption bands is performed based on the calculations of normal modes (NMs) and the potential energy distribution (PED). The bands most sensitive to the substituent nature belong to vibrations with prevalent involvement of ring CC and CO bonds and some low-frequency noncharacteristic NMs involving the Х atom. In support of the single crystal XRD data, intermolecular interactions have the strongest effect on the characteristic bands of the BF₂ moiety in the ranges 1280-1220 cm^-1 and 875-835 cm^-1; the sequences of IR band frequency shifts in a series of substituents corresponding to these interactions are reported.

The article examines the electronic structure and orbital nature of luminescence excitation in a series of molecular crystals with the general formula E _n AX₆, where E_n are organic and inorganic cations (diphenylguanidinium, guanidinium, and cesium); n is the number of cations; AX₆ are Te(IV) and Sb(III) anions; X are the atoms of halogens Cl or Br. The electronic structure of these molecular crystals is determined from the data of X-ray photoelectron spectroscopy of the core and valence levels and еру quantum chemical modeling фе the density functional theory level together with the previously obtained single crystal X-ray diffraction data.

The effect of an additional aromatic ligand on the electronic structure of nickel(II) and cobalt(II) bis-acetylacetonates is studied by XPS and DFT (B3LYP/def2-TZVPP). An analysis of atomic charges, the geometry of compounds, the electron density distribution, and the interaction of molecular orbitals of complex components allows the conclusion about the ionic nature of the bonding between the neutral ligand and the bis-chelate.

By UPS spectroscopy of vapor, XPS spectroscopy of the condensed phase, and quantum chemical methods the adducts of tris -b-diketonates Eu(асас)₃Phen and Eu(hfас)₃Phen are studied. The electronic structure and features of the nature of chemical bonds in the adducts are established. The geometric structure of the studied compounds in the gas phase is determined. A procedure is developed that helps to assign the bands in gas-phase HeI photoelectron spectra and also in the valence band of the XPS spectra. Quantum chemical calculations (DFT) make it possible to find the regular changes in the electronic structure of the chelate complexes depending on ligand fluorination, to study the effect of a 1,10-phenanthroline molecule on the electronic structure of the chelate rings, and also to analyze the electronic effects caused by trifluoromethyl substitution for methyl groups in the ligand.

X-ray photoelectron spectroscopy and quantum chemistry methods are used to study Nd(tol)₃ and Nd(сor)₃ carboxylate complexes and their adducts with 1,10-phenanthroline (Nd(tol)₃Phen and Nd(сor)₃Phen₂). The electronic structure and specific features of the nature of chemical bonds are studied, as well as the effect of 1,10-phenanthroline on the electronic structure of the adduct. We propose the band assignment of the valence band of the XPS spectra of all compounds.

A series of Ni- and/or Cu-containing coatings formed by plasma electrolytic oxidation on aluminum and titanium are examined by X-ray photoelectron spectroscopy. Binding energies of core electrons, elemental composition, chemical state of elements, and features of the structural organization of the surface and near-surface layers of the coatings are determined. A combination of the data collected indicates similar regularities of the composition and significant distinctions in the structure of the coatings formed. It is shown that the coatings formed on titanium are characterized by a considerably higher phosphorus concentration, and correspondingly, phosphates, unlike the coatings formed on aluminum, in which base metal and 3 d element (Ni or Cu) oxides are dominant. In both cases, Cu is mainly concentrated in the surface layers of the coatings whereas Ni is mainly concentrated in the near-surface layers.

Mineral valleriite of the Talnakh deposit, which consists of alternating copper-iron sulfide layers and brucite-like layers of magnesium-aluminium hydroxide is studied for the first time by XPS at photon excitation energies ranging from 1.253 keV to 6 keV and CuL FeL, SL, AlL, MgK, and OK edge TEY XANES using synchrotron radiation. The comparison of the XPS and XANES spectra of valleriite and chalcopyrite, in particular, demonstrates that in the sulfide layers of valleriite, Cu⁺ and Fe³⁺ are in a tetrahedral coordination, however, a local positive charge on both cations is slightly lower than that in chalcopyrite, apparently, due to a structure disorder. The concentration of oxygen-bound iron decreases with an increase in the depth of the analyzed layer even after ion etching; probably, Fe does not enter into the brucite-like layer, but mainly forms its own surface structures.

XPS, Pb L ₃ and Cu K EXAFS, solid state NMR, and EPR techniques are used to study insoluble products formed in the interaction of aqueous solutions of lead(II) nitrate and copper (II) sulfate with potassium n -butylxanthogenate (PX). The XPS spectra of lead xanthogenates with the composition PbX₂ are similar to those of PX, and interatomic distances of 0.279 nm suggest a nearly ionic character of Pb-S bonds. In copper xanthogenate precipitating together with dixanthogene (approximately 15 wt.%), the Cu(I)-S bond length is smaller (0.229 nm), and copper coordination number of 2.9 in a composite with dixanthogene increases to 3.3 after its removal by washing with acetone. The XPS spectra indicate the covalent character of the bond and non-equivalence of xanthogenate radicals. Solid state ¹H and ¹³C NMR spectra as well as the actual absence of metal lines under the measurement conditions demonstrate strong disordering of the structure of xanthogenates, which is stronger for PbX₂ and weakest in CuX after the removal of dixanthogene. EPR reveals sulfur-containing radicals and Cu²⁺ in CuX, however, their amounts are insignificant and decrease after the washing with acetone. The results of the work are significant for the understanding of the reactivity of xanthogenates, in particular, under the conditions of flotation beneficiation of base metal ores.

The states of components of highly efficient Pt/CeO₂ catalysts for low-temperature oxidation of carbon monoxide are studied in detail by X-ray photoelectron spectroscopy (XPS). Using the precise calibration of the spectra relative to the internal standard and the fitting of Ce3d and Pt4f spectra by elementary doublets, we found the features of the platinum interaction with the ceria lattice. It is shown that when the co-deposition technique is used, depending on the quality of stock solutions, it is possible to obtain both homogeneous solid solutions of platinum in the ceria lattice and solutions containing polyatomic platinum associates of the (PtO)_m type. It is found that when homogeneous PtCeO_x solid solutions are stored in air at room temperature, the homogeneous solutions slowly pass into the state of solutions with platinum associates. Mechanical mixtures of metallic platinum and ceria nanoparticles, synthesized by laser ablation, were also investigated in the course of their annealing in the air. The results obtained from the Pt4f spectra completely confirm the specific features of the interaction of platinum with ceria.

The regularities of the electron energy dissipation found in the subsurface atomic layer are valid in the bulk of a solid, too. On the example of model graphite-based materials it is shown that energy losses in X-ray photoelectron spectra agree with the calculated valence electron excitation spectra in analogous unit cells. The control of conjugate electron transitions opens the way to gain new data on the geometry, character, and order of bonding between atoms in the sample by the conventional electron spectroscopy and quantum chemistry methods.

The electronic structure of hexanuclear Mn(II,III) pivalate complexes with tetrahydrofuran and isonicotinamide are studied by X-ray photoelectron spectroscopy and X-ray emission spectroscopy. It is shown that when isonicotinamide substitutes for tetrahydrofuran the spin state of manganese ions is retained, and the electron density increases on the manganese and oxygen atoms of the [Mn₆(O)₂Piv₁₀] core.

X-ray photoelectron spectroscopy (XPS), X-ray emission spectroscopy (XES), and near edge X-ray absorption fine structure (NEXAFS) spectroscopy are used for in situ studies of the electronic structure of lithiated natural graphite produced by thermal deposition of lithium upon graphite in a vacuum. By XPS and NEXAFS spectroscopy it is found that lithium vapor thermal deposition results in the formation of a lithiated graphite surface layer and a change in its electronic structure. Based on the quantum chemical simulation of the experimental СK_α XES spectrum of lithiated graphite, it is found that lithium atoms are located mostly on the edges of graphite crystallites. Atomic force microscopy reveals that the size of natural graphite flakes varies from 50 nm to 200 nm.

The electronic structure and functional composition of the products of graphite oxide (GO) interaction with concentrated sulfuric acid (H₂SO₄) depending on the oxygen content in the precursor and the treatment temperature are studied. X-ray photoelectron spectroscopy measuring the near-edge Xray absorption fine structure at the CK edge, and infrared spectroscopy are used to show the reduction of the π-electron system of graphene planes at a temperature of 200° C. Aggregation of oxygen groups in GO containing more than 40 % of oxygen causes the formation of vacancy defects in the planes with oxygen groups at the edges. When the GO treatment temperature rises to 280°C, the oxidation of the basal plane π-regions occurs. The results can be the basis to control the functional composition, vacancy number and size in graphite materials.

The functional composition and electrochemical behavior of the samples of N121 oxidized nanodisperse technical carbon in aqueous electrolytes are studied. For oxidation 30% aqueous hydrogen peroxide (H₂O₂) solution and 2% H₂O₂ with the addition of singlet oxygen or ozone were used. By means of X-ray photoelectron spectroscopy data and the analysis of the near edge X-ray absorption fine structure the features of the chemical structure of the samples are found. The oxygen concentration did not exceed 5 at.% in the samples. The analysis of cyclic voltammograms reveals that at low potential sweep rates the specific capacity of the material is determined by the functional composition of the surface. The sample oxidized by 30% H₂O₂ solution and containing the largest number of -OH and -COOH groups demonstrated the highest capacity in 6M KOH and in 1М H₂SO₄ it was the sample with the highest concentration of C=O groups formed during the oxidation with singlet oxygen. The stability of carbon electrodes is studied in supercondensor models.

The work reports the study of the structure of carbon nanoparticles prepared by pyrolysis of helium-diluted acetylene under adiabatic compression in a piston reactor. At a pushing gas pressure of 0.5 MPa, 0.7 MPa, and 0.9 MPa the reaction gas heated to a temperature of 400° C, 600° C, and 750° C. By transmission electron microscopy it is found that carbon nanoparticles have a spherical form and their size varies from 20 nm to 60 nm. The structural features of carbon nanoparticles are determined from the Xray photoelectron spectroscopy data and the analysis of near-edge Xray absorption fine structure. Carbon nanoparticles prepared at a pushing gas pressure of 0.5 MPa have an amorphous structure and consist of hydrogenated carbon with an impurity of polycyclic aromatic fragments. At a stronger compression ratio, carbon nanoparticles with a layered structure consisting of mainly sp ² hybridized carbon atoms form. The capacitance properties and electrochemical impedance of electrodes based on carbon nanoparticles in supercapacitors are compared.

Monolayer carbon framework nanoparticles (nanohorns) (CNHs) are synthesized by two methods: electric arc and electron evaporation of graphite in the inert atmosphere. Based on the data of electron microscopy and Raman light spectroscopy distinctions in the structures of materials obtained by different methods are revealed. By X-ray photoelectron and NEXAFS spectroscopy a change in the chemical structure of the CNH surface during their oxidation is considered. It is found that oxidation causes the destruction of CNH agglomerates and weakly affects the structure of graphene nets. However, these changes are sufficient for an increase in the infrared radiation absorption by the dispersion of nanohorns in water. It is shown that the efficiency of laser heating with a wavelength of 808 nm of CNH dispersion depends on the synthesis method and chemical modification of nanoparticles, which enables their potential use for local hyperthermia of cells of living organisms in cancer therapy.

The Cu(II)GHK (Cu(II)-Gly-His-Lys (glycyl-hystidyl-lysine) complex is of interest as a model peptide for the elaboration of a procedure to study the structure of metal centers in proteins, in particular, the copper binding center in β-amyloid. X-ray absorption spectra are measured for an aqueous solution of Cu(II)GHK. The stability of the complex under X-ray radiation is controlled by optical spectroscopy. Structural models with different coordinations of the copper center, which were constructed based on the crystallographic structure, are considered. Based on the analysis of theoretical X-ray absorption spectra of the derived structures, two optimal models are chosen. For the selected models the structural parameters are optimized. It is found that the best agreement with the experiment is observed for the spectrum of a five-coordinated model with water molecules in the equatorial and lower axial positions with Cu-O distances of 1.97 Å and 2.31 Å respectively.

The electronic energy structures of three phosphorus-containing sulfides are studied from the experimental K and L_2,3 X-ray emission spectra, K absorption spectra of sulfur and phosphorus, X-ray photoelectron spectra, and also quantum chemical calculations based on density functional theory (DFT). The full-potential and all-electron quantum chemical calculations are carried out using the LAPW+lo basis set implemented in the WIEN2k software package [1]. The following exchange-correlation potentials are used for the calculations: PBE, PBE+U, and mBJ [2]. The spin-orbit coupling of Tl 5d_3/2 and 5d_5/2 electronic states are taken into account in Tl₃PS₄. All the specific features of the electronic energy structures of the compounds under study are determined in the valence and conduction bands near the Fermi level. The obtained band gaps Eg are in good agreement with the literature experimental data.

A series of Cu, Ni, and Mn complexes based on formylpyrone and formylcoumarine azomethynes with 1,3-diaminepropanol-2. The analysis of XANES and EXAFS spectra of the Cu, Ni, and Mn complexes, which were processed by both Fourier and wavelet transforms, enables the determination of local atomic structural parameters and the unambiguous evidence of the formation of both dimeric and monomeric structures for these coordination compounds. The possibility of forming binuclear compounds is shown to depend mainly on the nature of the bridging ligand and be independent of the type of the polydentate azomethyne ligand: pyrone or coumarine. The obtained structural results are well consistent with the magnetochemical data for the complexes.

Nanocomposite systems based on ternary semiconductor compounds ZnS _x Se_1-x with different compositions (x = 0, 0.3, 0.5, 0.7, 1) in dielectric matrices of nanoporous anodic alumina (AA) are synthesized by ultrahigh vacuum thermal sputtering of a mixture of lead sulfide and selenide powders. The effect of the atomic concentration of solid solutions and structural parameters of the AA template matrix on the crystal structure of synthesized nanocomposites and the local atomic environment of Zn and Se atoms is investigated.