1. Department of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice 370 05, Czech Republic
2. Division of Chemical Physics, Department of Chemistry, Lund University, Box 142, Lund SE-221 00, Sweden
3. Department of Chemistry, Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice 370 05, Czech Republic