1. Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
2. Department of Chemistry, Department of Materials Science and Nanoengineering, Smalley Curl Institute and NanoCarbon Center, Rice University, Houston, Texas 77005, United States
3. Department of Chemistry, Faculty of Science, Toho University, Funabashi, Chiba 274-8510, Japan