1. Laboratoire de Chimie Théorique (LCT), Namur Institute of Structured Matter (NISM), UNamur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
2. Unité de Recherche Lasers et Spectroscopies, Namur Institute of Structured Matter (NISM), UNamur, Rue de Bruxelles, 61, B-5000 Namur, Belgium