Growth, experimental and theoretical investigations on 4-hydroxy-3-methoxybenzaldehyde 5-chloro-2-hydroxybenzoic acid: A new high second order nonlinear optical material.

Novel 4-hydroxy-3-methoxy benzaldehyde 5-chloro-2-hydroxybenzoic acid (4H5C) organic co-crystal was grown by simple solution growth technique. 4H5C crystal exhibits the orthorhombic structure with non-centrosymmetric space group of Pna2 1 from single crystal X-ray diffraction study results. The cut-off wavelength and optical excitation wavelength was evaluated by using UV–Visible and PL spectral studies to the 4H5C heterodimer and suitability for the NLO applications are discussed. 4H5C single crystal material thermal stability and decomposition states were examined by using TG-DSC analysis. Vickers microhardness test was carried out on the flat surface of 4H5C crystal to understand the mechanical strength and behavior for weight loadings. Chemical etching patterns of 4H5C crystal surface was carried out and found the layer growth pattern. The second harmonic generation (SHG) efficiency of 4H5C single crystal was evaluated by Kurtz-Perry powder technique and result is compared with KDP crystal SHG efficiency. Polarizability, first order hyperpolarizability, geometric parameters of 45HC were evaluated theoretically by using B3LYP, CAMB3LYP methods of density functional theory by using 6-311++G (d,p) basis set. It is estimated that, the polarizability (3.38 x 10−23 e.s.u) and first order hyperpolarizability (9.370 x 10−30 e.s.u.) to the 4H5C heterodimer in B3LYP method. Image 1 • 4H5C crystal belongs to orthorhombic crystal system with spacegroup Pna2 1. • The high optical transmittance with lower cut-off wavelength at 370 nm. • Thermal analysis indicated that the crystal has melting point at 174.50 °C. • The 4H5C crystal belongs to soft kind of materials. • The high value of SHG efficiency exhibits NLO applications. [ABSTRACT FROM AUTHOR]