M. Vennila - University of Madras
R. Rathikha - Presidency University
S. Muthu - Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu, India
A. Jeelani - Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu, India
Ahmad Irfan