1. Charles University in Prague, Faculty of Mathematics and Physics, V Holešovičkách 2, 182 00 Prague 8, Czech Republic
2. Institute of Physics of the Academy of Sciences, Cukrovarnická 10, 162 53 Prague 6, Czech Republic
3. Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde, Denmark