1. Department of Chemistry, Reed College, Portland, Oregon 97202-8199, United States
2. Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
3. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
4. Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States