1. Department of Physics, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21215, USA
2. Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, USA
3. Department of Physics, Kansas State University, 1228 N. 17th St., Manhattan, Kansas 66506, USA
4. Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 2121, USA