1. Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
2. Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
3. Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, United States
4. Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
5. Department of Physics, University of Nevada, Reno, Nevada 89557, United States