[1] UCL, Dept Chem, London WC1E 6BT, England
[2] Univ Barcelona, Dept Quim Fis, E-08028 Barcelona, Spain
[3] Univ Barcelona, Inst Quim Teor & Computat IQTCUB, E-08028 Barcelona, Spain
[4] Univ Pablo Olavide, Dept Phys Chem & Nat Syst, Seville 41013, Spain
[5] ICREA, E-08010 Barcelona, Spain