1. Department of Engineering Physics, Polytechnique Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, QC H3C3A7, Canada
2. Department of Chemistry, St. John's University of Tanzania, P.O. Box 47 Dodoma, Tanzania
3. NT-MTD Spectrum Instruments, 5861 S Kyrene Rd#19, Tempe, AZ 85283, USA