1. Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707, USA
2. Department of Physical and Applied Sciences, University of Houston-Clear Lake, Houston, TX 77058, USA
3. Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
4. Department of Mathematics and Physics, North Carolina Central University, Durham, NC 27707, USA