1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
2. Instituto de Física “Gleb Wataghin”, UNICAMP, 13083-859 Campinas, São Paulo, Brazil
3. Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
4. Institute for Solid State and Materials Physics, Technical University of Dresden, 01062 Dresden, Germany
5. Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States