1. Department of Chemistry, Bowman-Oddy Laboratories, University of Toledo, Toledo, Ohio 43606
2. Department of Physics, University of Stockholm, Box 6730, S-113 85 Stockholm, Sweden
3. GSF-Forschungszentrum fuer Umwelt und Gesundheit, Institut fuer Oekologische Chemie, D-85758 Oberschleissheim, Germany