1. National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei 230029 P. R. China
2. Department of Chemical Physics; University of Science and Technology of China; Hefei 230026 P. R. China
3. Hefei National Laboratory for Physical Sciences at the Microscale; Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei 230026 P. R. China