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Fluorinated graphite intercalation compounds (FGICs) with acetonitrile C2Fx · yCH3CN (x = 0.92, 0.69, and 0.49) have been synthesized using a gaseous mixture of BrF3 and Br2 at room temperature and subsequent replacement of the reaction medium components on acetonitrile by isopiestic method. The change in functional composition and electronic structure of FGICs under annealing at 250–260 °C was studied by infrared, X-ray photoelectron, and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) methods. Analysis of the data revealed interaction of acetonitrile with a C2Fx matrix. The X-ray spectra detected formation of new nitrogen species attributed to two-coordinated and mono hydrogenated three-coordinated atoms. Mechanism of nitrogen incorporation in the fluorinated graphene layers was proposed. Schematic structure of graphite fluoride C2Fx intercalated with acetonitrile and NEXAFS N K-edge spectrum of C2F0.69 · 0.137CH3CN before and after annealing at 250 °C.

We present a detailed study on the physical properties of single crystals of the Eu3+ intermetallic EuCo2Si2. The Eu valence was confirmed by X-ray absorption. At low temperatures, the anisotropic susceptibility can be explained by a Eu3+ Van Vleck contribution with a crystal field parameter , but at high temperatures the data exceed the Van Vleck values significantly. This excess susceptibility is possibly related to the magnetic exchange between the excited Eu multiplets and the conduction band. A γ of 9.6 mJ K−2 mol and a Debye temperature of 322 K were estimated from the low temperature specific heat data. The compound does not undergo any phase transition in the temperature range 2–300 K.

D. Haberer*,1, L. Petaccia2, Y. Wang3, H. Quian3, M. Farjam4, S. A. Jafari4,5, H. Sachdev6,7, A. V. Federov8, D. Usachov8, D. V. Vyalikh8,9, X. Liu10, O. Vilkov8,9, V. K. Adamchuk8, S. Irle3, M. Knupfer1, B. Buchner1, and A. Gruneis1,10 1 IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany 2 Elettra Synchrotron Light Laboratory, Sincrotrone Trieste SCpA, S.S. 14 Km 163.5, 34149 Trieste, Italy 3 Department of Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan 4 Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran 5 Department of Physics, Sharif University of Technology, Tehran 11155-9161, Iran 6 Anorganische Chemie 8.11, Universitat des Saarlandes, 66041 Saarbrucken, Germany 7 Max-Planck-Institut fur Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany 8 St. Petersburg State University, St. Petersburg 198504, Russia 9 Institut fur Festkorperphysik, TU Dresden, Mommsenstrasse 13, 01069 Dresden, Germany 10 Faculty of Physics, University of Vienna, Strudlhofgasse 4, 1090 Wien, Austria

Pristine and fluorinated single-wall carbon nanotubes (SWCNTs) irradiated by Ar+ ion beam with kinetic energy 1 keV have been studied using C K-edge X-ray absorption near-edge spectroscopy (XANES). Theoretical spectra used for interpretation of the experiment were plotted based on density functional theory (DFT) calculations of graphene fragment contained different types of defects (single-atom vacancy, carbon adatom, oxygen or fluorine functionalized vacancy) within Z + 1 approximation. Comparison between experimental and theoretical spectra shows that ion irradiation creates vacancies and boundary atoms of defects readily interact with oxygen yielding ether groups mainly.

Angle-resolved photoemission spectra of Ce, Yb, and Eu systems reveal dispersions and momentum dependent energy splittings of the 4f emissions that are obviously caused by the interaction of localized 4f states with delocalized valenceband states. The spectra may be described satisfactorily in the light of a simplified approach of the periodic Anderson model by a momentum dependence of the electron hopping matrix elements. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report on a systematic approach to exploit the potential of filled carbon nanotubes (CNT) to act as sensors that might provide non-invasive temperature control in biological systems on a cellular level. In this case the temperature is detected by measuring NMR parameters on the filling materials. The beneficial feature of a carbon nanotube is to provide protection of both (i) a human body against toxic adverse effects from the filling material and (ii) a filling material against chemical and biochemical exposure. The feasibility of this concept has been demonstrated on the example of the temperature-dependent NMR frequency and relaxation time measured on the CNT filled with the appropriate sensor materials.

Multiwall CN x nanotubes have been grown in the result of acetonitrile decomposition over Fe catalyst (CVD method). The random nanotubes samples have been produced by classical technique using catalyst nanoparticles formed by iron bimaleate thermolysis. The aligned nanotubes have been synthesized by aerosol assisted CVD method where ferrocene was used as a catalyst source. X-ray photoelectron spectroscopy (XPS) showed the random sample contains two kinds of nitrogen, while additional high-energy peak was detected in the N Is-spectrum of the aligned CN x nanotubes. X-ray absorption spectra measured near the N K-edge (NEXAFS) of the samples exhibited three peaks for both type of CN x nanotubes. The relative intensity of the high-energy peak was found to be much higher in the spectrum of aligned nanotubes. Assignment of the NEXAFS peaks was made using results of quantum-chemical calculations on carbon tube model incorporating pyridinic, three-fold coordinated and molecule nitrogen. The high-energy peak was shown to correspond to N 2 molecules and its absence in the XPS spectrum of random CN x nanotubes indicates the gaseous nitrogen is mainly concentrated in the interior region of nanotubes. The larger encapsulation of molecules in the aligned CN x nanotubes could be due to the higher diffusion of nitrogen atoms trough the catalytic particles formed directly in the CVD process.