1. State Key Laboratory of Electroanalytical Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun Jilin 130022 P. R. China
2. University of Chinese Academy of Science; Beijing 100039 P. R. China
3. College of Physics; Jilin University; Changchun Jilin 130012 P. R. China
4. Department of Chemistry and Physics; State University of New York at Stony Brook; Stony Brook NY 11794-3400 USA