effectiveness.According to the literature data [13-15], the adsorption activity of organic
molecules and, hence, their susceptibility to chemisorption can be estimated by the
reactivity indices, various electronic structure parameters obtained as a result of
quantum-chemical calculations with regard for the electronic and energy
characteristics of the inhibitor and the metal.Therefore, a prognostic estimate of the
adsorption capacity based on the electronic characteristics of molecules such as the
energy of the higher occupied molecular orbital (E
HOMO
) and the energy of the lower
vacant molecular orbital (E
LUMO
), the energy of the molecular gap (Δε = E
HOMO
–E
LUMO
)
was carried out, electronegativity and chemical hardnessof a molecule based on the
theory of functional densitythe extract apricot pomace.
According to the literature data, the adsorption of organic matter occurs on the
partially filled d-orbitals of Ferum by the reaction centers of molecules. It has been
established that corrosion inhibitors usually promote the formation of a chelate on the
metal surface, which include the transfer of electrons from the organic compounds to
the metal, forming a donor-acceptor bond during the chemical adsorption process.
According to Koopman’s theorem [13-15], the frontier orbital energies E
HOMO
and
E
LUMO
are related to the ionization potential, I, and the electron affinity, A, of iron and
the inhibitor molecule by the following relations: A =−E
LUMO
, I =−E
HOMO
. In this
adsorption, the metal acts as an electrophile while the inhibitor acts as a nucleophile.
Considering the charge transfer characteristics of the adsorption, the wide use of
quantum chemical calculations to study this process is justified. Calculated electron
charges on the atoms of molecules were determined by their ability to chemical
interaction, and by the wave function of the higher occupied molecular orbital and the
lower free molecular orbital, the most probable adsorption centers and the predictive
adsorption capacity of the compounds were determined. In addition, it is known that
the more a negative charge on a heteroatom, the better the transfer of electrons from
the donor occurs. Taking into account the characteristics of the transfer of charge of
adsorption, the literature substantiates the widespread use of quantum-chemical
calculations for the study of this process [13-15]. Quantum chemical calculations have
been performed by the HyperChem 7 package. The geometry optimization was
obtained by application of the restricted Hartree-Fock method (RHF) using MNDO
approach with PM3 parameterization.
Pearson and Parr were presented definitions using the finite differences method
depending on electron affinity (A) and ionization energy (I) of any chemical species
(atom, ion or molecule) for chemical hardness (η), and chemical potential (χ)
According to the theory of functional density, the absolute electronegativity (χ),
chemical potential (μ) are the main parameters that characterize the ability of molecules
to chemically interact [13-15]. The chemical potential, electronegativity, chemical
hardness of an electronic system is defined as:
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