1. Department of Geosciences, State University of New York at Stony Brook, New York 11794-2100, Institut für Geologie, Mineralogie, Geophysik, Ruhr-Universität-Bochum, 44801 Bochum, Germany, NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8562, and Department of Chemistry, State University of New York at Stony Brook, New York 11794-2100