1. Beijing Key Laboratory for Terahertz Spectroscopy and Imaging, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics; Capital Normal University; Beijing 100048 People's Republic of China
2. Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy; Institute of Atomic and Molecular Physics, Jilin University; Changchun 130012 People's Republic of China
3. Beijing Institute of Applied Physics and Computational Mathmatics; Beijing 100094 People's Republic of China
4. Institute of Theoretical Chemistry, Jilin University; Changchun, Beijing 130023 People's Republic of China