1. a Department of Physics , Colorado State University , Fort Collins , CO , 80523 , USA
2. b Hochdrucklabor bei der Universität Potsdam , Postfach 60 16 32, D-14416 , Potsdam , Germany
3. c Universität Ulm, Organische Chemie III, Albert-Einstein-Allee 11 , D-89069 , Ulm , Germany
4. d Department of Chemistry , Colorado State University , Fort Collins , CO , 80523 , USA
5. e Texas Center for Superconductivity , University of Houston , TX , 77204 , USA