Results 1 - 10 of 31705
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[en] Momentum resolved inelastic electron energy loss has been exploited to measure the surface and bulk plasmons of ErAs(100). The effects of the electronic band structure are seen in the weak plasmon dispersion, and a contribution to the surface and bulk plasmons, from the Er 5d bands, is indicated in the decrease in the surface plasmon frequency by about 10% from the free electron value and to a ratio of the bulk and surface plasmon energies of about √3
[en] A complementary approach is proposed for analysing series of electron energy-loss spectra that can be recorded with the spectrum-line technique, across an interface for instance. This approach, called blind source separation (BSS) or independent component analysis (ICA), complements two existing methods: the spatial difference approach and multivariate statistical analysis. The principle of the technique is presented and illustrations are given through one simulated example and one real example
[en] A hybrid model of lepton-nuclear interactions is constructed; energy loss spectra and average muon and tau lepton energy losses in inelastic scattering off nuclei in rock and water in the energy range 102–109 GeV are calculated in the framework of this model. Charge asymmetry of scattering due to processes with weak neutral current is discussed. Comparison with calculations in the framework of other models is presented.
[en] High purity polycrystalline samples of C60 and C70 were obtained and studied by the electron energy-loss spectroscopy in the reflection mode. The spectra were used for determination of the loss functions of fullerenes. Loss functions of the fullerenes were compared with those of graphite. It was established that the relative intensities of the peaks corresponding to (σ+π)- and π-plasmons depended on the primary electron energy, while the (σ+π)-plasmon energies did not depend on the primary electron energy and were equal to 25.0 eV for C60 and 24.8 eV for C70. The conclusion on the space localization for plasma occilations in fullerenes was made on the base of the study of the energy dependent loss functions. (orig.)
[en] The properties of one-dimensional (1D) plasmons are rather unexplored. We investigated the plasmonic collective excitations, measured as one-dimensional plasmon dispersions with electron energy loss spectroscopy, highly resolved both in energy and lateral momentum, for both phases of Au induced chains on stepped Si(553) substrates. We observe 1D dispersions that are strongly influenced by the lateral chain width and by the interchain coupling. Indications for the existence of two different plasmons originating from two surface bands of the systems are given for the low coverage phase. (paper)
[en] Aberration-corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy has been used to determine the distribution of Cu and Ag atomic columns of precipitates in an Al–Mg–Si–Cu–Ag alloy. Cu columns were commonly part of C and Q′ phases, with the atomic columns having large projected separations. Columns containing Ag were more tightly spaced, in areas lacking repeating unit cells and at incoherent precipitate–host lattice interfaces. Cu-rich and Ag-rich areas were not found to intermix
[en] Full text: As an extension of previous work, we present preliminary calculations for the dielectric properties of the silicon (100) surface. In particular, the |q|→0 and |q|=2π/a(1,0,0) surface loss function, and corresponding surface plasmon energies have been calculated within a simple model for the silicon surface. The results have been obtained from the Adler and Wiser dielectric matrix (DM). The bandstructure used for the calculation was based on the highly successful empirical pseudopotential method of Cohen and Chelikovsky. We have used a 59 plane wave basis for the bandstructure, and have chosen a DM size of 59 x 59. Results are compared and contrasted with volume plasmon calculations, free electron calculations and experiment
[en] Highlights: • Electron energy-loss spectra in the backward scattering in pyridazine were measured. • Vertical excitation energies of the dipole-forbidden and spin-forbidden triplet states of pyridazine were determined. • Assignments of the dipole-forbidden and spin-forbidden triplet states were proposed. • Systematic trends in the energy shifts of the correlating triplet and singlet states of the diazine molecules were observed. - Abstract: Excitation of the valence electronic states of the pyridazine molecules in the gas phase have been studied using the technique of electron energy-loss spectroscopy. Varying the electron scattering conditions, the residual electron energy and scattering angle, enabled the optically-allowed and -forbidden excitations to be differentiated. The measured energy-loss spectra enabled the vertical excitation energies of the observed states to be determined and tentative assignments for them to be obtained. Comparison of the available vertical excitation energies of the correlating triplet and singlet states of the diazine molecules, pyridazine, pyrimidine and pyrazine, allowed systematic trends in the energy shifts to be determined.
[en] In this work we present an experimental study of the intercalation of the graphene/Ni(111) system by cesium atoms. The evidence of a complete alkali intercalation has been obtained by Auger and angle-resolved electron-energy-loss measurements. The changes in the electronic and vibrational properties demonstrate that a weakly bonded graphene layer can be synthesized on Ni(111) by means of Cs intercalation. - Highlights: • A complete intercalation of graphene/Ni(111) system by Cs atoms has been obtained. • From graphene/Ni(111) to graphene/Cs/Ni(111): EELS evidences • Intercalation of Cs atoms makes the epitaxial graphene on Ni(111) quasi-free