1. National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373, United States
2. Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487-0336, United States
3. Theoretical Chemistry Group, Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
4. Department of Physical and Inorganic Chemistry, Universitat Rovira i Virgili, C. Marcel·lí Domingo 1, 43007 Tarragona, Spain
5. Department of Physical Chemistry and Institut de Química Teòrica i Computacional, Universitat de Barcelona, 08028 Barcelona, Spain
6. ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain