1. Deparment of Chemistry and The Center for Electron Transport in Molecular Nanostructures, Columbia University, New York, New York 10027, United States
2. Department of Chemistry, The Univeristy of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
3. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
4. National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, United States
5. Nakamura Functional Carbon Cluster Project, ERATO, Japan Science and Technology Agency, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan