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 βHRS up to 2.8×102 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.