1. Department of Inorganic Chemistry, Institute of Chemistry, Faculty of Sciences, P.J. Šafárik University in Košice, Košice, Slovakia
2. Departamento de Química Inorgánica, Instituto de Sintesis Química y Catálisis Homogénea (ISQCH), CSIC-University of Zaragoza, Zaragoza, Spain
3. Slovak Academy of Sciences, Institute of Experimental Physics, Košice, Slovakia
4. Institute of Physics, Faculty of Sciences, P.J. Šafárik University in Košice, Košice, Slovakia