1. Institute of Theoretical Physics and College of Physics and Electromechanical Engineering, Hexi University, Zhangye 734000, People's Republic of China
2. School of Science, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
3. Joint Laboratory of Atomic and Molecular Physics of NWNU & IMPCAS and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, People's Republic of China