1. Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, Athens 15310, Greece, Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O. Box 1385, GR-711 10 Heraklion, Crete, Greece, Department of Physical Chemistry, Palacky University, Olomouc 77146, Czech Republic, and Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853