1. Department of Chemistry and Biochemistry; California State University; Northridge CA 91330 USA
2. Beijing Computational Science Research Center; Beijing 1 0084 P.R. China
3. Department of Chemistry & Chemical Biology; Cornell University; Ithaca NY 14853 USA
4. Geophysical Laboratory; Carnegie Institution of Washington; 5251 Broad Branch Rd. NW Washington DC USA
5. Department of Civil and Environmental Engineering; The George Washington University; Washington DC 20052 USA
6. Lawrence Livermore National Laboratory; Livermore CA 94550 USA