1. Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, ul. Grudziądzka 5, 87-100 Toruń, Poland
2. Department of Chemistry and Center for NanoScience (CeNS), LMU Munich, Butenandtstr. 5-13, 81377 Munich, Germany
3. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland