1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo Náměstí 2, Praha 6, Praha 166 10, Czech Republic
2. Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University, Technická 2, Praha 6, Praha 166 27, Czech Republic
3. Institute of Plasma Physics, Czech Academy of Sciences, Za Slovankou 3, Praha 182 00, Czech Republic
4. Institute of Physics, Czech Academy of Sciences, v. v. i., Cukrovarnická 10, Praha 162 00, Czech Republic