1. Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, P. R. China
2. Academy
for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, P. R. China
3. Center
for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons,
Beijing National Laboratory for Molecular Sciences, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, P. R. China