1. J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
2. Institut fur Ionenphysik und Angewandte Physik, Universitat Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
3. Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 166 28 Prague, Czech Republic