Abstract:
Quantum chemical calculations based on DFT method were performed on azomethine compound: PhN=N-C
(COCH3) =NC6H4Y {Y = NO2 (SB1)}used as corrosion inhibitor for mild steei in acid media to determine the
relationship between the molecular structure of (SB1 )and inhibition efficiency. The structural parameters, such
as the frontier molecular orbital energy HOMO (highest occupied molecular orbital) and LUMO (lowest
unoccupied molecular orbital), the charge distribution of the studied inhibitor, the absolute electronegativity (χ)
values, and the fraction of electrons (ΔN) transfer from inhibitor to iron, were also calculated and correlated with
inhibition efficiencies. The results showed that the inhibition efficiency of (SB1) increased with the increase in
ELUMO and decrease in ELUMO - EHOMO; and the areas containing N atoms are most possible sites for bonding the
metal iron surface by donating electrons to the metal
