1. Ångström
Laboratory,
Department of Chemistry, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
2. Chemistry Department, Theoretical
Chemistry Division, Lund University, Box
124, SE-22100 Lund, Sweden
3. Laboratory of Organic and Macromolecular
Chemistry, Friedrich-Schiller-Universität Jena, Humboldtstr. 10, D-07743 Jena, Germany