DFT studies on D–π–A substituted bis-1,3,4-oxadiazole for nonlinear optical application

In the present work, we have synthesized novel D–π–A substituted bis-1,3,4-oxadiazoles derivatives and studied nonlinear optical properties using density functional theory (DFT). The FT-IR and ¹H NMR data confirmed the structure of the molecule. The HOMO–LUMO, energy band gap, molecular electrostatic potential map, and global chemical reactivity descriptors were estimated using the DFT and TD-DFT with B3LYP, CAM-B3LYP and WB97XD using 6-31G (d) levels basis set and results show all synthesized molecules have excellent chemical hardness, chemical potential, excellent chemical strength, and excellent chemical stability. The static and dynamic linear polarizability, first hyperpolarizability and second hyperpolarizability components were estimated using time-dependent density functional theory. The first-order hyperpolarizability β (2x; x, x) computed at a wavelength of 1064 nm was found to be 55 times greater than the urea molecule. The dynamic molecular second-order hyperpolarizabilities γ (−3x;x,x,x) suggested good nonlinear properties for the designed molecule.