ELECTRONIC STRUCTURE OF OCTAVINYLAND OCTAPHENYLSILSESQUIOXANE FROM XPS AND DFT DATA
I. S. Os’mushko, V. I. Vovna, V. A. Yashin, V. V. Korochentsev, M. V. Tutov, N. P. Shapkin
Far Eastern Federal University, Vladivostok
vovna@vido.dvgu.r
Keywords: polyhedral siloxanes, XPS, DFT, electronic structure
Abstract
X-ray photoelectron spectroscopy (XPS) and density functional theory are employed to study the electronic structure of octasilsesquioxanes (RSiO1.5)8 with vinyl and phenyl terminal groups. Quantitative compositions determined from the XPS data are close to those estimated by empirical formulas. Narrow spectral lines corresponding to ionization from C1s core levels indicate similar chemical states of carbon atoms for both compounds. Experimental data are confirmed by close calculated values of effective charges on carbon atoms when polarization functions are included in the basis set and also by small energy ranges of core level electrons. The valence spectral region is interpreted based on the calculated energy values of electronic levels with regard to the density of states and ionization cross-sections.
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