1. II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
2. U Bremen Excellence Chair, Bremen Center for Computational Materials Science, and MAPEX Center for Materials and Processes, University of Bremen, D-28359 Bremen, Germany
3. I. Institute of Theoretical Physics, Universität Hamburg, D-22607 Hamburg, Germany
4. NanoLund and Division of Mathematical Physics, Department of Physics, Lund University, SE-22100 Lund, Sweden
5. The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany