1. Department of Chemistry, Hallym University, ChunCheon, KangWonDo, 200-702, Korea, KFKI Atomic Energy Research Institute, P.O. Box 49, H-1525 Budapest, Hungary, Institute of Experimental Physics, University of Debrecen, H-4026 Debrecen, Hungary, and Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610, Antwerpen, Belgium