1. Department of Physics, GC University Lahore, Katchery Road, Lahore 54000, Pakistan
2. Department of Physics, COMSATS Institute of Information Technology, Lahore 54000, Pakistan
3. Instituto de Astrofisica de Canarias, 38205 La Laguna, Tenerife, Spain and Departamento de Astrofisica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
4. Department of Physics, Quaid-e-Azam University, Islamabad 45320, Pakistan