1. Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
2. Institute of Experimental Physics, Faculty of Mathematics, Physics and Informatics, University of Gdańsk, Wita Stwosza 57, Gdańsk 80-308, Poland
3. Institute for Superconducting & Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
4. National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan