Structural and electronic properties of heptachlor

Abstract

In this work, the molecular geometry of heptachlor is investigated using ab initio HF, DFT, LDA, and GGA methods. The natural bond orbital (NBO) analysis is performed at the B3LYP/6-311++G(d,p) level of theory. The first order hyperpolarizability βtotal, the mean polarizability Δα, the anisotropy of the polarizability Δα, and the dipole moment μ, are calculated by B3LYP/6-311++G(d,p) and HF/6- 311++G(d,p) methods. The first order hyperpolarizability (βtotal) is calculated based on the finite field approach. UV spectral parameters along with HOMO, LUMO energies for heptachlor are determined in vacuum and the solvent phase using HF, DFT, and TD-DFT/B3LYP methods implemented with the 6-311++G(d,p) basis set. Atomic charges and electron density of heptachlor in vacuum and ethanol are calculated using DFT/B3LYP and TD-DFT/B3LYP methods and the 6-311++G(d,p) basis set. In addition, after the frontier molecular orbitals (FMOs), the molecular electrostatic potential (MEP), the electrostatic potential (ESP), the electron density (ED), and the solvent accessible surface of heptachlor are visualized as a results of the B3LYP/6-311++G(d,p) calculation. Densities of states (DOS), the external electric field (EF) effect on the HOMO-LUMO gap, and the dipole moment are investigated by LDA and GGA methods.