1. a Institute of Physics, University of Neuchâtel , CH-2009 Neuchâtel, Switzerland
2. b Department of Chemistry , University of Engineering and Technology , Lahore 54890, Pakistan
3. c Department of Chemistry , King Fahd University of Petroleum and Minerals , Dhahran 31261, Saudi Arabia
4. d PAEC , P.O. Box 1114, Islamabad GPO 44000, Pakistan
5. e Department of Chemistry , University of Sargodha , Sargodha, Pakistan