Geometrical Structure, Vibrational Spectra, NLO, NBO, Electronic Transitions and Thermo Dynamical Analysis of 5-Fluoro-2-Methylbenzonitrile by DFT Computational Method

Abstract

Equilibrium geometric structure of 5-fluoro-2-methylbenzonitrile (5F2MBN) has been carried out through quantum mechanical calculations aided by Density Functional Theory (DFT) theory. Geometrical parameters (bond length, bond angle and dihedral angle) are predicted by using the DFT levels employing B3LYP method with 6-311++G (d, p), cc-pvdz and Aug- cc-pvdz as basis sets. The FT-IR and FT-Raman spectra of the 5F2MBN were recorded and analyzed by the same level of theory. Frequency doubling and Second Harmonic Generation (SHG) applications are exist in the title molecule, so that the Non Liner Optical (NLO) properties are calculated by the same method with different basis sets. Stability of the molecule occurring from hyper conjugative interactions, charge delocalization has been investigated by Natural Bond Orbital (NBO) analysis. The FMOs (Frontier Molecular Orbitals) reports energies and properties of many electron states. These FMOs is very important for predicting the optical and electric properties of the molecule. The various thermodynamic properties like entropy, enthalpy, Gibbs free energy, and elevated heat energy have been calculated. At last Molecular Electrostatic Potential (MEP) derived charges were also identified by the same theoretical calculations.