1. Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
2. Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
3. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, United States
4. Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States