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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 1 Issue 1 (1998) pp 11-17
The electronic structure of $\mathsf{(C_{59}N)_2}$ from high energy spectroscopy
S. Haffner (1) (a), T. Pichler (1), M. Knupfer (1), B. Umlauf (1), R. Friedlein (1), M.S. Golden (1), J. Fink (1), M. Keshavarz-K. (2), C. Bellavia-Lund (2), A. Sastre (2), J.C. Hummelen (2), F. Wudl (2)
(1) Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden, Germany
(2) Institute for Polymers and Organic Solids, Department of Chemistry and Materials, University of California, Santa Barbara, California 93106, USA
Received: 25 August 1997 / Revised: 22 September 1997 / Accepted: 16 October 1997
Abstract: We report the results of a detailed study of the occupied and unoccupied electronic structure of dimers of the new heterofullerene $\rm C_{59}N$ by means of photoemission and electron energy-loss spectroscopy. A close similarity is found between the electronic structures of pristine $\rm (C_{59}N)_2$ and $\rm C_{60}$ with an additional broadening of the spectra in the former due to the distortion of the fullerene cage caused both by dimerization and the chemical substitution. Both the occupied and unoccupied electronic states, as well as the interband transitions between them, attest to the high degree of molecular character retained in the solid state. Comparison of the shake-up structures in the $\rm C1s$ and $\rm N1s$ X-ray photoemission spectra confirm that the highest lying occupied states in the heterofullerene have a strong degree of N character, whereas the lowest lying unoccupied states have mainly C character. We also present the optical conductivity of the heterofullerene (derived from the loss function), which shows an optical gap of 1.4 eV, some 0.4 eV smaller than that of $\rm C_{60}$.
PACS. 71.20.Tx Fullerenes and related materials; intercalation compounds - 79.60.Fr Polymers; organic compounds - 78.90.+t Other topics in optical properties, condensed matter spectroscopy and other interactions of particles and radiation with condensed matter
(a) e-mail: haffner@ifw-dresden.de
Online publication: February 4, 1998
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