1. Institute of Physics, Faculty of Physics and Astronomy, University of Zielona Góra, Z. Szafrana 4a, 65-516 Zielona Góra, Poland
2. Department of Superconductivity and Phase Transitions, Division of Physics of Dielectrics and Molecular Spectroscopy, Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
3. Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland