1. Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, P.O.
Box 1033, Blindern, N-0315 Oslo, Norway
2. Haldor Topsøe A/S, Haldor Topsøes Allé 1, DK-2800 Kongens Lyngby, Denmark
3. Center for Molecular Modeling, Ghent University, Technologiepark 903, B-9052 Zwijnaarde, Belgium