1. Empa—Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
2. Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
3. ETH Zurich, Ion Beam Physics, Otto-Stern-Weg 5, 8093 Zurich, Switzerland