1. Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Départment de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France
2. Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
3. Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA