Computational, experimental investigations on effect of phosphoric acid to enhance the linear and nonlinear optical properties of hexamine p-nitrophenol crystal.

Phosphoric acid influenced the crystal structure of hexamine p-nitrophenol and their physico-chemical properties. Supermolecular assembly of hexamine, p-nitrophenol, phosphoric acid and water (HNPP) crystal was grown through slow evaporation process in acetone–water solvent. The HNPP crystal exhibits both second harmonic generation (SHG) and third order nonlinear consequences. Single crystal XRD reveals that the HNPP crystal belongs to monoclinic system with space group P21/c. To confirm structure, computational/investigational IR and UV–visible spectra were analysed. The molecular absorption, transparency and optical energy gap of HNPP was measured from experiments and compared to calculate TD-DFT quantities. The UV spectral wavenumbers of molecule were evaluated and the appropriate FMO intermolecular transitions into α (↑ ) and β(↓) offsets were assigned. The HNPP crystal is being used for the fluorescence spectral analysis. The powder SHG effect was obtained from Kurtz and Perry procedure is 0.73 times superior to standard urea. As well as, the static first hyperpolarizability value is 3.8 times superior to urea. Z-scan technique revealed that the HNPP possess third order nonlinear efficiency. The NLO and MEP, as well as Fukui functions were used to discuss the charge of the global molecule and local atoms respectively. [ABSTRACT FROM AUTHOR]