1. Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
2. Institute
for Theoretical Physics, University of Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany
3. Department
of Chemistry and Department of Physics, University of Toronto, 80 St. George Street, Toronto, Canada M5S 1H6
4. The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany