1. Mulliken Center for Theoretical Chemistry, Clausius-Institut Für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, Bonn 53115, Germany
2. Center for Research Computing and Department of Chemistry, University of Pittsburgh, 312, Schenley Place, 4420 Bayard Street, Pittsburgh, Pennsylvania 15260, United States
3. Dipartimento di Chimica “Giacomo Ciamician”, Universitá di Bologna, Via F. Selmi 2, Bologna 40126, Italy
4. Department of Chemistry, University of Cologne, Greinstrasse 4-6, 50939, Köln, Germany