Vibrational spectroscopic investigations, first hyperpolarizability, HOMO-LUMO and NMR analyzes of p-fluorobenzonitrile

Abstract

Quantum chemical density functional calculations were carried out for PFBN with the GAUSSIAN 09W using ab initio and Becke-3-Lee-Yang-Parr (B3LYP) functional. The observed FT-IR and FT-Raman vibrational frequencies are analyzed and compared with theoretically predicted vibrational frequencies. The geometries and normal modes of vibration obtained from DFT method are in good agreement with the experimental data. The first-order hyperpolarizability (β) of the investigated molecule was computed using DFT calculations. The calculated HOMO and LUMO energies shows that charge transfer occur within molecule. The influences of nitrogen on the geometry of benzene and its normal modes of vibrations have also been discussed. The UV-Vis spectral analysis of PFBN has also been done which confirms the charge transfer of PFBN. The chemical shifts of H atoms and C atoms were calculated using NMR analysis.