1. MIFP, ETSF, Physics Department of Tor Vergata University, Via della Ricerca Scientifica 1, I-00133 Rome, Italy
2. Department of Chemistry and Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern, N-0315 Oslo, Norway
3. MIFP, V. Lashkarev Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, pr. Nauki 45, UA-03680 Kiev, Ukraine
4. Institut für Chemie, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
5. Département de Chimie, École Normale Supérieure, 24 rue Lhomond, F-75005 Paris, France