1. Department
of Chemistry and
Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
2. Quantum Theory Project, University of Florida, Gainesville, Florida 32611,
United States
3. Theoretical Division, Center for
Nonlinear Studies (CNLS) and Center for Integrated Nanotechnologies
(CINT), Los Alamos National Laboratory,
Los Alamos, New Mexico 87545, United States