Investigation of Conformation, Vibration and Electronic Properties of 2- Methoxythiophene Molecule by Theoretical Methods

Abstract

In this study, the structural parameters, vibrational frequency, the electronic energy, the dipole moment, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy, the polarizability, hyperpolarizability and the potential energy curves (PEC) of 2-methoxythiophene molecule were calculated at Hartree-Fock (HF) and Density Functional Theory (DFT) with B3LYP (Becke 3 Parameter Lee-Yang-Parr) model using the 6-311++(d,p) basis set in gas phase. The potential energy curves of the molecule were performed as a function the θ[C3-C2-O-C6] torsion angle varying from 0-360º at 10º intervals. The dipole moment value of the molecule was calculated as 1.99 Debye by the DFT/B3LYP/6-311++G(d,p) method and as 2.24 Debye by the HF/6-311++G(d,p) method, respectively. The obtained vibrational wave numbers were scaled with appropriate scale factors and the assigning of these vibrational wavenumbers was made according to the potential energy distribution (PED) using the VEDA 4f program. Also, by using HOMO-LUMO energies, energy gap values, ionization energy, electron affinity, chemical potential, electronegativity, hardness and softness indices were obtained. The approximate geometry of the molecules in three dimensions was drawn in the GaussView 5.0 molecular imaging program, and all theoretical calculations were used with the Gaussian 09W package.