Investigation on growth, crystal structure, third-order optical nonlinearity properties and DFT computational studies of novel proton transfer 3-ami- nopyridine P-nitrobenzoate P-nitrobenzoic acid (3APPNB) single crystal for third-order NLO applications

A new organic single crystal of 3-aminopyridine p-nitrobenzoate p-nitrobenzoic acid (3APPNB) with a size of 8 x 4 x 2 mm(3) was grown by slow evaporation solution growth technique at room temperature using methanol solvent. The lattice parameter values were evaluated with the help of single crystal XRD and it confirms that the 3APPNB crystal belongs to triclinic crystal structure and the space group P-1. Crystal unit cell parameters are a = 9.3384(5) angstrom, b = 10.0403(5) angstrom, c = 11.094(6) angstrom, alpha = 109.4940(10)degrees, beta = 93.964(2)degrees, gamma = 99.890(2)degrees and V = 957.03 (9) (angstrom(3)) were determined. The 3APPNB crystal crystallizes in a centrosymmetric nature, triclinic system and space group P-1. SCXRD study shows that both the anion and the cation are interlinked to each other by two types of symmetrical intermolecular C-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonds. The crystalline nature and hkl phases have been determined using Powder XRD studies. The presence of different vibrational groups in the 3APPNB compound is examined by employing Fourier transform infrared (FT-IR) spectral analysis. UV-Vis-DRS spectral analysis signifies that the 3APPNB has a wide transmittance (98 %) and a cut-off wavelength of around 317 nm. The etch pit density (EDP) of 3APPNB crystal was examined by a chemical etching analysis. The thermal studies expose that 3APPNB is thermally stable up to 172 degrees C. The surface morphology of the 3APPNB is analyzed by SEM. The nonlinear properties like beta, n(2) and chi((3)) were measured through the Z-scan analysis and the values were calculated to be 5.78 x 10(-5) m/W, 8.05 x 10(-12) m(2)/W) and chi((3)) = 8.936 x 10(-9). The third-order nonlinear optical (TONLO) chi((3)) values are higher. The achieved TONLO chi((3)) value when compared to other similar constituents is owing to the tarnish movement of pi-electron configuration from the donor to an acceptor that makes the molecules highly polarized. The results reveal that the 3APPNB crystal finds applications in devices like optical switching and optical limiting. The quantum-chemical theoretical analyses are performed to measure the intrinsic properties of the 3APPNB molecules using DFT calculation. The band gap, orbital energy and second hyperpolarizability are also studied using changing the applied field. Furthermore, Quantum chemical calculations are used to obtain the MESP, HOMO-LUMO and first-order hyperpolarizability for the 3APPNB compound.