1. Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA
2. Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6373, USA
3. Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
4. Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
5. Ghent Quantum Chemistry Group, Department of Chemistry, Ghent University, Krijgslaan 281 (S3), B-9000 Gent, Belgium
6. Department of Chemistry of the University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium