1. Department of Physics, Islamia College University, Peshawar, Pakistan;
2. Department of Applied Physics, Federal Urdu University of Arts, Science and Technology, Islamabad, Pakistan;
3. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China;
4. Department of Chemistry, Islamia College University, Peshawar, Pakistan;
5. Department of Physics, Riphah International University, Islamabad;
6. Department of Chemistry, University of Azad Jammu and Kashmir, Azad Kashmir, Muzaffarabad, Pakistan;
7. Department of Physics, University of Agriculture Faisalabad, Faisalabad, Pakistan