1. Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 116 35 Athens, Greece
2. Otto Schott Institute of Materials Research, Friedrich-Schiller-Universität Jena, Fraunhoferstrasse 6, 07743 Jena, Germany
3. National Technical University of Athens, Zografou Campus, 15780 Athens, Greece