[1] Natl Renewable Energy Lab, Mat Chem & Computat Sci, Golden, CO 80401 USA
[2] Colorado Sch Mines, Dept Phys, Golden, CO 80401 USA
[3] Univ Calif Berkeley, Applied Sci & Technol Grad Grp, Berkeley, CA 94720 USA
[4] Lawrence Berkeley Natl Lab, Energy Technol Area, Berkeley, CA 94720 USA
[5] Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA