1. Department of Chemistry, University of California, Berkeley, CA 94720, USA.
2. Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
3. Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
4. Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.