1. University of California Lawrence Livermore National Laboratory, L-356, 7000 East Avenue, Livermore, California 94551
2. Stanford Linear Accelerator Center, MS 69, 2575 Sand Hill Road, Menlo Park, California 94025
3. Fundamenteel Onderzoek der Materie (FOM) Institute for Atomic and Molecular Physics (AMOLF), P.O. Box 41883, 1009 DB Amsterdam, The Netherlands
4. University of California Lawrence Livermore National Laboratory, L-470, 7000 East Avenue, Livermore, California 94551
5. Department of Chemistry, Brown University, Providence, Rhode Island 02912