1. Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
2. Department of Chemistry, The University of Dalat, 670000 Dalat, Vietnam
3. Laboratory of Solid State Physics and Magnetism and Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
4. Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University of Leipzig, Linnestrasse 2, D-04103 Leipzig, Germany