1. Ruhr-Universität Bochum, Physical Chemistry I, Universitätsstr. 150, D-44801 Bochum, Germany
2. Leibniz Universität Hannover, Institut für Festkörperphysik, Appelstr. 2, D-30167 Hannover, Germany
3. Department of Chemistry, Fudan University, Shanghai 200438, People’s Republic of China
4. Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K.