1. Laboratoire des Mécanismes Réactionnels, UMR CNRS 7651, Ecole Polytechnique, F-91128 Palaiseau Cedex, France, Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Group of Computational Chemistry, Faculty of Chemical Engineering, HoChiMinh-City University of Technology, Vietnam