1. Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K.
2. Key Laboratory for Advanced Materials, Centre for Computational Chemistry and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
3. National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan
4. Department of Physics, National Tsing Hua University, Hsin-chu 30013, Taiwan