1. James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
2. Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA
3. Program in the Biophysical Sciences, Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
4. The College, The University of Chicago, Chicago, Illinois 60637, USA
5. Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA