1. Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996
2. Materials Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
3. Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
4. Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071
5. Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803
6. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831