1. Lehrstuhl für Physkalische Chemie II Ruhr Universität Bochum 44801 Bochum Germany
2. Chemical Sciences Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA
3. Kenneth S. Pitzer Center for Theoretical Chemistry University of California Berkeley California 94720 USA
4. Department of Chemistry University of California Berkeley California 94720 USA
5. Department of Chemical and Biomolecular Engineering University of California Berkeley California 94720 USA
6. Department of Bioengineering University of California Berkeley California 94720 USA