1. Institut
de Química Teòrica i Computacional, Universitat de Barcelona, Barcelona 08028, Spain
2. Departament
de Química Física, Universitat de Barcelona, Barcelona 08028, Spain
3. Departament
de Química Orgànica, Universitat de Barcelona, Barcelona 08028, Spain
4. IBM Research Zurich, Säumerstrasse
4, 8803 Rüschlikon, Switzerland
5. Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
6. Center for Free-Electron Laser Science & Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
7. Nano-Bio Spectroscopy Group and ETSF, Departamento Fisica de Materiales, Universidad del País Vasco, CFM CSIC-UPV/EHU-MPC & DIPC, 20018 San Sebastián, Spain