1. Institut Charles Gerhardt Montpellier, UMR 5253, Université de Montpellier, ENSCM, CNRS, Place E. Bataillon, 34095 Montpellier Cedex 5, France.
2. CFisUC, Department of Physics, University of Coimbra, 3004-516 Coimbra, Portugal.
3. Physics Department and CICECO–Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
4. Fédération de Recherche Chimie Balard–FR3105, Université de Montpellier, Place E. Bataillon, 34095 Montpellier Cedex 5, France.