1. Department of Analytical Chemistry, University of Chemistry and Technology, Prague, 166 28 Prague 6, Czech Republic
2. Institute of Physics of the Czech Academy of Sciences, 182 21 Prague 8, Czech Republic
3. Department of Solid State Chemistry, University of Chemistry and Technology, Prague, 166 28 Prague 6, Czech Republic
4. Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States