1. J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic
2. Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud 11, 91405 Orsay, France
3. Instituto de Física, Universidade Federal Fluminense, 24210-340, Niterói, RJ, Brazil