LAUSR

ABSTRACT First and second order hyperpolarizabilities of, 2-hydroxy-5-methylbenzaldehyde (HMB) and its related three molecules 2, 6-hydroxy-3-methyl acetophenone (HMA), 5-ethyl-2-hydroxybenzaldehyde (HBA) and 2, 6-Dihydroxy-4-methyl benzaldehyde (DMB) were calculated by employing MP2 (Moller-Plesset) method. The vibrational behavior of the title molecule was extracted by using Fourier transform infrared, Fourier transform-Raman analysis. The UltraViolet-visible spectrum recorded and analyzed using ethanol solvent, reveals the optical and electronic transition properties. Hydrogen and carbon nuclear magnetic resonance spectra were also recorded. Kurtz and Perry powder technique was utilized to examine the second harmonic generation effectiveness. The third-order nonlinear optical performances and optical limiting threshold are investigated by Z-scan techniques. The experimental results of SHG and Z-scan strongly proved the NLO behaviour of the HMB molecule. The optical limiting value is 19.64 Jcm−2 indicating that the HMB molecule could be a promising candidate for optical limiting materials. Potential energy surface scanning has been performed to discover the stability of the molecules which leads to the nonlinear optical activity. The geometry optimization has been performed to analyze the nonlinear optical active site with bonding features. Natural bond orbital analysis, Hirshfeld surface analysis, density of energy states, Frontier molecular orbital analysis, molecular electrostatic potential, Fukui function and global reactivity descriptor have also been carried out to verify the nonlinear optical activity. The natures of intramolecular hydrogen bonds are analyzed using QTAIM and RDG analysis.