1. Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
2. Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Louisiana 70504, United States
3. Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
4. Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
5. Department of Physics, University of Central Florida, Orlando, Florida 32816, United States