1. Institute of Molecule and Crystal Physics, Ufa Federal Research Centre, Russian Academy of Sciences, Prospekt Oktyabrya 151, 450075 Ufa, Russia
2. Università di Bologna, Centro Interdipartimentale di Ricerca in Scienze Ambientali, via S. Alberto 163, 48123 Ravenna, Italy
3. St. Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia