1. Institute of Chemistry of New Materials and Center of Physics and Chemistry of New MaterialsUniversität Osnabrück Barbarastrasse 7 49076 Osnabrück Germany
2. Department of PhysicsUniversität Osnabrück Barbarastrasse 7 49076 Osnabrück Germany
3. School of Environmental SciencesHull University Hull HU67RX U.K.