1. Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
2. Department of Physics, University of California, One Shields Avenue, Davis, California 95616, United States
3. Physics Department, Georgetown University, Washington, D.C. 20057, United States
4. Thermal Energy Conversion Research and Advancement Group, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, United States
5. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States