1. State Key Laboratory of Crystal MaterialsShandong University Jinan 250100 China
2. School of PhysicsShandong University Jinan 250100 China
3. Department of ChemistryNorth Carolina State University Raleigh NC 27695‐8204 USA
4. State Key Laboratory of Structural ChemistryFujian Institute of Research on the Structure of Matter (FJIRSM)Chinese Academy of Sciences (CAS) Fuzhou 350002 China