1. Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland
2. Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straaae 38, 01187 Dresden, Germany
3. Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland