1Institute of Inorganic Chemistry of the Czech Academy of Sciences, 250 68 Husinec-Řež, Czech Republic
2Faculty of Environment, Králova výšina 7, J.E. Purkyně University in Ústí nad Labem, 400 96 Ústí nad Labem, Czech Republic
3Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague 6, Czech Republic
4Military Resarch Institute, Veslařská 230, 637 00 Brno, Czech Republic
5Faculty of Electrical Engineering, Czech Technical University, Technická 2, 166 27 Prague 6, Czech Republic
6Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, P.O. Box 534, SE-751 21 Uppsala, Sweden