1. Department of Inorganic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
2. Chair of Theoretical Chemistry, Technische Universität Dresden, Bergtrasse 66c, 01062 Dresden, Germany
3. Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Permoserstr. 15, 04318 Leipzig, Germany