1. The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
2. Deutsches Elektronen–Synchrotron DESY, 22607
Hamburg, Germany
3. Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
4. Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
5. Department of Chemistry, Aarhus University,
8000 Aarhus C, Denmark
6. Helmholtz Zentrum Dresden Rossendorf, 01328
Dresden, Germany
7. Center for Free–Electron Laser Science, Deutsches Elektronen–Synchrotron DESY, 22607 Hamburg,
Germany
8. Center for Ultrafast Imaging, Universität Hamburg, 22761 Hamburg, Germany
9. Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
10. Max Planck Institute for Biophysical Chemistry, 33077 Göttingen, Germany
11. Institute for X-ray Physics, Göttingen University, 33077 Göttingen, Germany
12. Department of Physics, Lund University, 22100
Lund, Sweden
13. Department of Physics, Universität Hamburg,
22761 Hamburg, Germany
14. J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA