1. Institute
for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
2. SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
3. DESY Photon Science, 22607 Hamburg, Germany
4. Department
of Physics, Stockholm University, 10691 Stockholm, Sweden
5. SUNCAT, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
6. LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
7. Physik
Department, Universität Hamburg and Center for Free-Electron Laser Science, 22761 Hamburg, Germany
8. Institut
für Physik und Astronomie, Universität Potsdam, 14476 Potsdam, Germany
9. Chapman University, Orange, California 92866, United States
10. Surface
Science Research Centre and Department of Chemistry, The University of Liverpool, Liverpool L69 3BX, United Kingdom
11. Department
of Applied Physics, KTH Royal Institute of Technology, 10691 Stockholm, Sweden
12. Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany