1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr D-45470, Germany
2. Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
3. Department of Physics, West University of Timisoara, Bd.V. Parvan No. 4, Timisoara 300223, Romania
4. Academy of Romanian Scientists, Ilfov 3, Bucharest 050044, Romania
5. Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia
6. CQUPT-BUL Innovation Institute & College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065, People’s Republic of China
7. Faculty of Science and Technology, Jan Długosz University, Armii Krajowej 13/15, Częstochowa PL-42200, Poland
8. Department of Molecular Theory and Spectroscopy, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr D-45470, Germany