1. M. Smoluchowski Institute of Physics, Jagiellonian University, S. Łojasiewicza 11, 30-348 Kraków, Poland
2. AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, al. A. Mickiewicza 30, 30-059 Kraków, Poland
3. Analytical Chemistry Department, Ivan Franko National University of Lviv, Kyryla and Mephodiya 6, 79005 Lviv, Ukraine