[1] Univ Sains Malaysia, Sch Phys, Usm 11800, Malaysia
[2] Univ Abuja, Dept Phys, Abuja 900211, Nigeria
[3] Univ Sains Malaysia, Adv Med & Dent Inst, Bertam 13200, Malaysia
[4] Univ Sains Malaysia, Sch Ind Technol, Usm 11800, Penang, Malaysia
[5] Univ Sains Malaysia, Sch Hlth Sci, Kota Baharu 16150, Kelantan, Malaysia
[6] Benue State Univ, Dept Phys, Makurdi 102119, Nigeria
[7] Univ Abuja, Dept Chem, Abuja 900211, Nigeria