Quantum Chemical Approach for the Study of the Phytoconstituents of Araucaria heterophylla Gum (AHG) as Corrosion Inhibitor Using Density Functional Theory (DFT)

Abstract

Corrosion experiments and quantum chemical study on the basis of density functional theory (DFT) were done using some of the phytoconstituents of Araucaria heterophylla gum (AHG) for mild steel (MS) corrosion in acidic media. The inhibition performance of the certain phytoconstituents of AHG was explored with the aid of quantum chemical parameters. Quantum chemical descriptors that are allied with the inhibition efficiency such as the highest occupied molecular orbital energy (EHOMO−), lowest unoccupied molecular orbital energy (ELUMO−), energy gap (ΔE), dipole moment (μ), global hardness (ɳ), global softness (S), ionization potential (I), electron affinity (A), electronegativity (χ), the fraction of electrons transferred (∆N), electrophilicity index (ω), chemical potential and ΔEBack − donation were determined. These theoretical findings were used to understand the mechanism of inhibition.