Structural, spectral, and third-order nonlinear optical analysis of solution-grown allylammonium hydrogen oxalate hemihydrate crystal for laser applications

An organic crystal, allylammonium hydrogen oxalate hemihydrate (AHOH) is grown by slow evaporation of the solvent. The cell constants and C2/c space group have been determined by single-crystal X-ray diffraction (SCXRD) analysis. Functional groups have been interpreted using FTIR spectral analysis, and their vibrational modes are assigned. Optical parameters like nature of transmittance, lower cutoff wavelength (225 nm), and optical band gap (Eg = 4.89 eV) are found using UV–Vis–NIR spectrum. The crystal exhibits its optical transparency from 225 nm and makes AHOH an ideal material to generate UV wavelengths. Transmission in the entire visible region makes it to be a suitable material in optoelectronic applications. 13C and 1H NMR spectroscopic analysis has been carried out to assess the molecular structure of AHOH. The third-order NLO characteristics have been found by Z-scan analysis, and AHOH manifests the saturable absorption and self-defocusing effects. These properties suit the crystal for optical sensors and optical switching applications. The third-order nonlinear optical susceptibility (χ3) is found to be 1.65206 ×\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document} 10−7 esu. The presence of N–H⋯O and O–H⋯O hydrogen bonds in the molecular structure is the reason for the observed high χ3 value. The results imply that AHOH is a good choice for NLO and optoelectronic applications.