1. Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
2. University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, SI-1000 Ljubljana, Slovenia
3. Lviv Polytechnic National University, 12 S. Bandera Street, UA-79013 Lviv, Ukraine
4. School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK