1. Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
2. National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
3. Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
4. Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, USA
5. Department of Mechanical Engineering, Center for Combustion and Environmental Research,University of Colorado, Boulder, Colorado 80309-0427, USA