1. Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
2. Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P.R. China
3. Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854
4. Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080