1. University of Bucharest, Faculty of Chemistry, Inorganic Chemistry Laboratory, Str. Dumbrava Rosie nr. 23, 020464-Bucharest, Romania
2. Institute of Chemistry, Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
3. National Institute for Laser, Plasma and Radiation Physics, Laboratory of Solid-State Quantum Electronics, P.O. Box MG-36, Magurele, 077125, Romania