1. Material Science and Engineering, University of Arkansas, Fayetteville, AR 72701, USA
2. Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA
3. Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
4. Department of Physics, Berea College, Berea, KY 40404, USA
5. Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
6. Department of Chemistry, Sokol Institute, Montclair State University, Montclair, NJ 07043, USA