1. Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4-6, D-53115 Bonn, Germany
2. Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
3. Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av Rovisco Pais 1, 1049 001 Lisboa, Portugal