1. Nanoscale Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
2. Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
3. Material, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
4. Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States