NLO azo compounds with sulfonamide groups: A theoretical investigation

The linear and nonlinear optical properties such as the dipole moment, polarizability, electric field-induced second harmonic generation, and hyper-Rayleigh scattering first hyperpolarizability of four heterocyclic azo compounds have been calculated and analysed extensively using density functional theory. The relationship between the structure, electric field-induced second harmonic generation, and hyper-Rayleigh scattering responses are evaluated. The relationship between the static first hyperpolarizability and energy gap is also taken into account. These azo compounds are found to have reduced HOMO-LUMO energy gap at the PBE0 level, large value of second order nonlinear optical susceptibility /3HRS up to 2.8 x 102 a.u. was obtained at the same PBE0 level, and a significant donor character in the case of HAC2, HAC3 and HAC4 azo compounds, these factors render them suitable for nonlinear optical applications.