1. a Institute of Physics National Academy of Sciences of Ukraine , prosp. Nauky 46, 252022 , Kyiv , Ukraine
2. b Institutfuer Phys. Chemie, Martin-Luther-Universitaet , Muehlphorte 1, 06108 , Halle (S) , Germany
3. c Institut fuer Tech. und Macromol. Chemie, Martin-Luther-Universitaet , 06108 , Halle (S) , Germany