1. Center
for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
2. The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
3. Department
of Physics, Lund University, Box 118, 221 00 Lund, Sweden
4. Faculty
of Science, Nano and Molecular Systems Research Unit, University of Oulu, Box 3000, FIN-90014 Oulu, Finland
5. Chemical
Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
6. Department
of Physics, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
7. Sorbonne Université, CNRS, Laboratoire de Chimie Physique - Matière et Rayonnement, LCPMR, F-75005 Paris, France
8. Department
of Physics, University of Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany
9. Department
of Physics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States