1. Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland
2. Laboratory of Ultrafast Spectroscopy and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
3. Department of Chemistry, University of Fribourg, Fribourg, Switzerland
4. Institute of Applied Physics, University of Bern, Bern, Switzerland
5. Department of Chemistry, University of Basel, Basel, Switzerland
6. Department of Chemistry, University of Zürich, Zürich, Switzerland
7. Department of Physics, ETH Zürich, Zürich, Switzerland
8. Department of Chemistry, University of California, Berkeley, California 94720, USA
9. Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
10. Department of Physics, Politecnico di Milano, 20133 Milano, Italy
11. SwissFEL, Paul-Scherrer Institute, Villigen, Switzerland
12. Paul-Scherrer Institute, Villigen, Switzerland
13. Institute for Chemical and Bioengineering, ETH Zürich, Zürich, Switzerland