Study of Nonlinear Optical Properties of a Self-Healing Organic Crystal

Recently a noncentrosymmetric single crystal of a dibenzoate derivative, namely, dimethyl-4,4'-(methylenebis(azanediyl))dibenzoate, with second harmonic generation activities at 405 nm and ultrafast self-healing activity was reported by Mondal et al. in <i>Nature Communications</i> in 2023. Here, the linear and nonlinear optical properties of this notable molecular crystal were simulated using 1,611,464 atoms in the Supermolecule approach at the DFT/CAM-B3LYP/aug-cc-pVTZ level. Our results for the second order nonlinear optical properties of dimethyl-4,4'-(methylenebis(azanediyl))dibenzoate show that the second harmonic generation is more significant at 532 nm. In addition, the density functional theory calculations of the electro-optical parameters for the crystals in the pristine state and after the fracture mechanical self-healing process show small differences, confirming the efficiency of the self-healing process. Additionally, the crystal displays significant third-order nonlinear optical properties, particularly pronounced at a shorter wavelength of 330 nm. Thus, the self-healing dimethyl-4,4'-(methylenebis(azanediyl))dibenzoate crystal shows relevant second and third order nonlinear optical properties which make it a very interesting material for optical applications.