1. National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
2. Department of Physics, Abdul Wali Khan University, Mardan 23200, Pakistan
3. Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
4. Section of Mathematics, International Telematic University Uninettuno, Corso Vittorio Emanuele II 39, 00186 Roma, Italy