1. Division of Science and Mathematics, Fordham University at Lincoln Center, New York, New York 10023
2. National Resource in Computational Chemistry, Lawrence Berkeley Laboratory, Berkeley, California 94720
3. Department of Chemistry and Center for Biological Macromolecules, State University of New York at Albany, Albany, New York 12222
4. Courant Institute of Mathematical Sciences, New York University, New York, New York 10012