1. Physics
and Astronomy Department, Michigan State University, East Lansing, Michigan 48824, United States
2. Center for Advancing Electronics Dresden (cfaed), 01062 Dresden, Germany
3. Theoretical
Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
4. Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
5. Institute
of Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany
6. National University of Science and Technology, MISIS, 119049 Moscow, Russia