1. Department
of Chemistry, Nankai University, Tianjin 300071, China
2. Theory of Nanomaterials Group and INPAC−Institute
of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
3. Department of Chemistry,
Missouri University of Science and Technology, University of Missouri, Rolla, Missouri 65409-0010, United States