V.V. Khvostov

Electronic structure of carbynes studied by Auger and electron energy loss spectroscopy

Abstract The experimental carbon Auger lineshape for two samples of carbyne has been obtained. The electronic structure of carbynes has been calculated by the self-deconvolution of experimental Auger spectra. Results are discussed in terms of the electronic properties of linear molecules with 2–6 carbon atoms. It is shown that both carbyne samples have a linear structure with cumulene-type bonds but with different numbers of atoms in the chain. The influence of annealing at T

Auger-spectroscopy studies of the electronic structure of amorphous carbon films

Abstract Information on the density of valence states (DOVS) of a-C films has been determined by Auger spectroscopy. The films were prepared by magnetron sputtering of graphite and plasma decomposition of hydrocarbon gas. The relative contents of graphite-like and diamond-like components in a-C have been determined by comparison of the area under the π-band of a-C with that of graphite. The effect of annealing on the a-C structure has been studied.

Transformation of diamond and graphite surfaces by ion irradiation

Abstract The densities of valence states (DOVS) of diamond and graphite have been determined by Auger-electron spectroscopy (AES). The DOVS of graphite fully compiles with theoretical data. The DOVS of diamond corresponds to reconstructed diamond surface. The effect of H+ ion irradiation on the DOVS of diamond and graphite is being considered. It has been shown that after H+ irradiation new maximums arise in DOVS of both carbon modifications.

Ion neutralization at ionic crystal surfaces

Abstract Results of experimental and theoretical investigations of low-energy ion–surface charge exchange on the surface of LiF single crystals are described. It is shown that, for adequate interpretation of experimental data on ion neutralization, it is important to use the exact overlap integrals of electron orbitals of interacting particles instead of the commonly used exp(− r / r 0 ) hopping integrals. The many-particle time-dependent Anderson–Newns Hamiltonian is used to describe ion–surface interaction.

Auger-spectroscopy studies of the 3d-band of copper oxides

The high resolution experimental copper Auger line-shape for copper and copper oxides (CuO, YBaCuO) has been obtained, corrected for the effects of the final state hole-hole interaction. As a result self-fold of local density of valence states has been yielded and Cu 3d-band has been determined by self-deconvolution procedure. Low temperature shrinkage of Cu 3d band for YBaCuO was found.

Electronic structure of alkali halide surfaces upon ion irradiation

Abstract By a careful analysis of the electron loss spectra of some alkali halide crystals after ion irradiation we have demonstrated that defect generation depends on ion energy nonmonotonously. This effect is connected with inelastic interaction between ion and surface atoms.

Synthesis of carbyne on the basis of polyvinylidene halides

IR and Auger electron spectroscopy and spectroscopy of characteristic energy losses of electrons have been used to study the reaction of dehydrohalogenation of polyvinylidene halides on exposure to an alcoholic solution of alkali in presence of THF. It is shown that on chemical dehydrohalogenation of the polyvinylidene halides the cumulene form of carbyne appears. The mechanism of the reaction is discussed. The scheme of the formation of the cumulene structure and the triple carbon-carbon bonds is proposed. It is whown that in the IR spectra of carbyne absorption of the cumulated double bonds is manifest in the region 1600 cm−1.

Features of the energy distribution of secondary particles upon the ion bombardment of graphite

The secondary emission of carbon atoms from the (0001) plane of graphite nanocrystallites bombarded with argon ions with energies of 1 and 10 keV and the incidence angle α = 45° is investigated. The unusual oscillating energy distributions of secondary C+ ions with main maxima Emax in the range of 40–60 eV and peaks corresponding to the energies E1 ≈ 20, 30, 70, 80, and 100 eV have been revealed. The C+ ion yield decreases, the energy spectrum increases, and the maximum Emax shifts to larger energies E1 with increasing emission angle (with respect to the normal to the surface). The secondary-ion emission from the (0001) face of graphite is numerically simulated with allowance for the charge exchange of secondary ions to obtain a qualitative explanation of the observed results.

Electronic structure of Cs-graphite surface studied by Auger-spectroscopy

The electronic properties of Cs-covered graphite surfaces at different Cs concentrations were studied by high resolution Auger-electron spectroscopy. The density of valence states (DOVS) was obtained by the self-deconvolution method. The band structure of Cs-graphite compounds was calculated by the Green function method. Two different models of the Cs-graphite interaction for two stages of intercalation were proposed. Characteristics of the Cs-graphite interaction were obtained from a comparison of experimental and calculated DOVS.

Resonance charge-exchange in ion scattering and sputtering at the SrTiO3 surface

Abstract Experimental studies of inelastic interaction of low-energy Ar + ions (200–1400 eV) with SrTiO 3 (100) surface are presented. The studies were performed by means of Auger spectroscopy, secondary ion mass spectroscopy and ion surface scattering. The oscillating dependence of the Sr ion yield on the incident Ar ion energy was found. The Sr ion yield and the scattered Ar ion intensity were oscillated in antiphase. The results are interpreted in terms of the quasi-resonant charge-exchange model. The performed simulation of the ion charge-exchange confirms the validity of the model used.