1. Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, P.O. Box 808 L-350, Livermore, California 94550, USA
2. Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, USA
3. High Pressure Collaborative Access Team, X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
4. Department of Geoscience, University of Nevada, Las Vegas, Nevada 89134, USA