1. Physics Department, National and Kapodistrian University of Athens, Panepistimioupoli, Zografoy, Athens 10679, Greece
2. INRS-Centre Énergie Matériaux Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes (Québec) J3X 1S2, Canada
3. Department of Physics, University of the Free State, P.O. Box, 339, Bloemfontein ZA9300, South Africa
4. Laboratory of Photochemistry and Kinetics, Department of Chemistry, University of Crete, VassilikaVouton, Heraklion 71003, Crete, Greece
5. Institute of Electronic Structure and Laser (IESL) Foundation for Research and Technology (FORTH), 100N. Plastirastr, VassilikaVouton, Heraklion GR-70013, Crete, Greece
6. Physics Department, University of Crete, VassilikaVouton, Heraklion GR-71110, Crete, Greece
7. Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa