1. Department
of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409, Texas United States
2. Institute
for Advanced Simulation, Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
3. Institute
for Theoretical Chemistry, University of Vienna, A-1090 Vienna, Austria
4. School
of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin, 300072 P.R. China