1. Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, N-9037 Tromsø, Norway
2. Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
3. Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
4. Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy