1. Department of Chemistry, New York University, 100 Washington Square East, Silver Building, New York, New York 10003, United States
2. Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, New York 10012, United States
3. New York University−East China Normal University Center for Computational Chemistry, New York University—Shanghai, Shanghai 200062, P. R. China
4. Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States