1. Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstraße 4, D-53115 Bonn, Germany
2. HQS Quantum Simulations GmbH, Rintheimer Straße 23, D-76131 Karlsruhe, Germany
3. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany