1. Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
2. Department of Physics, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
3. Institute of Chemistry, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590 Pakistan
4. Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad 22060, Pakistan