Experimental and computational study on molecular structure, natural bond orbital and natural hybrid orbital analysis of non-linear optical material trans-3-(o-hydroxyphenyl-1-phenyl)-2-propen-1-one

• Stable conformer of trans-3-(o-hydroxyphenyl-1-phenyl)-2-propen-1-one has been identified.
• The vibrational spectra of trans-3-(o-hydroxyphenyl-1-phenyl)-2-propen-1-one were analyzed.
• Charge transfer characteristics were examined by HOMO–LUMO and NBO analysis.
• Thermodynamic properties were determined at different temperatures.

Fourier transform infrared and Fourier transform Raman spectra of trans-3-(o-hydroxyphenyl-1-phenyl)-2-propen-1-one (or simply 2-hydroxychalcone) were recorded in the regions 4000–400 cm−1 and 3500–100 cm−1, respectively in the solid phase. The vibrational frequencies were calculated by Hartee-Fock and density functional B3LYP methods with 6-311++G(d,p) basis set, using Gaussian 09W program package. A detailed interpretation of the infrared and Raman spectra of 2-hydroxychalcone is reported. The thermodynamic functions of the title compound were also studied by the above methods and the basis set. The stability of the molecule arising from hyper conjugative interactions and accompanying charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The linear polarizability (α) and the first order hyperpolarizability (β) values of the investigated molecule have been computed using DFT quantum mechanical calculations. The HOMO and LUMO energy gap reflects the chemical activity of the molecule. The observed and calculated wave numbers are found to be in good agreement.