1. Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The...