1. Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, Private Bag 102904, 0745 Auckland, New Zealand
2. Mulliken Center for Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany
3. Institute of Hydrogen Technology, Helmholtz-Zentrum Hereon, Max-Planck-Strasse 1, D-21502 Geesthacht, Germany