1. Institute of Theoretical Chemistry; Jilin University; Changchun 130023 P.R. China
2. College of Chemistry; Jilin University; Changchun 130012 P.R. China
3. Fachbereich Chemie; Philipps-Universität Marburg; 35032 Marburg Germany
4. Donostia International Physics Center (DIPC); P.K. 1072 20080 Donostia Euskadi Spain