1. Fk. 4, Physik, Bergische Universität Wuppertal, Gauss-Straße
20, D-42097 Wuppertal, Germany
2. Department of Chemistry, Faculty of Science, Toho University, Chiba 274-0072, Japan
3. Department of Physical Chemistry, Plovdiv University “Paisii Hilendarski”, Tsar Asen Str. 24, 4000 Plovdiv, Bulgaria
4. Institute of Physics, Bijenička
cesta 46, P.O. Box 304, HR-10002 Zagreb, Croatia