[1] Northwestern Univ, Dept Chem & Biol Engn, Evanston, IL 60208 USA
[2] Sandia Natl Labs, Mat Phys & Chem Sci Ctr, Albuquerque, NM 87185 USA
[3] Univ Texas Rio Grande Valley, Dept Chem, Edinburg, TX 78539 USA
[4] Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA
[5] Univ Minnesota, Chem Theory Ctr, Minneapolis, MN 55455 USA
[6] Georgia Inst Technol, Sch Chem & Biomol Engn, Atlanta, GA 30332 USA
[7] NIST, Div Chem Sci, Gaithersburg, MD 20899 USA