1. Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
2. Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
3. Department of Physics, Universität Hamburg, Luruper Chaussee 149, Hamburg 22761, Germany
4. Instituto Carlos I de Fı́sica Teórica y Computacional and Departamento de Fı́sica Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada, Spain
5. Department of Chemistry, Universität Hamburg, Luruper Chaussee 149, Hamburg 22761, Germany