1. Current address: Department of Chemistry and Chemical Engineering, Chalmers Univeristy of Technology, 41296 Gothenburg (Sweden)
2. Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark)
3. School of Chemistry, The University of Sydney, NSW 2006, Sydney (Australia)
4. Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby (Denmark)
5. Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark)