1. Theoretical Physical Chemistry, Research Unit Molecular Systems, B6c, University of Liège, B4000 Liège, Belgium
2. Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
3. Department of Chemistry and the PULSE Institute, Stanford University, 333 Campus Drive, Stanford, California 94305, United States
4. SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States