1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China, Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory and College of Physics, Qingdao University, Qingdao 266071, P. R. China, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China, and Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011