1. Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska,
68588, United States
2. Department
of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania
15260, United States
3. Department
of Chemistry, Key Laboratory
of Environmentally Friendly Chemistry and Applications of Ministry
of Education, Xiangtan University, Hunan
Province, China 411105
4. Department of Chemistry, Brown University, Providence, Rhode Island 02912, United
States