1. Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons, Belgium
2. Department of Physics and NTIS, University of West Bohemia, Univerzitní 8, 306 14 Plzeň, Czech Republic
3. Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
4. Materia Nova Research Center, Parc Initialis, B-7000 Mons, Belgium