1. Physics Department and Science of Advanced Materials Ph.D. Program, Central Michigan University, Mt Pleasant, Michigan 48859, USA
2. Institute of Theoretical Physics, TU Bergakademie Freiberg, 09596 Freiberg, Germany
3. Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
4. Department of Physics, Government College University, 38040 Faisalabad, Pakistan