Inhibition efficiencies of three amino acids
[tryptophan (B), tyrosine (c), and serine (A)] have been
studied as green corrosion inhibitors on corrosion of carbon
steel using density functional theory (DFT) method in gas
and aqueous phases. Quantum chemical parameters such as
EHOMO (highest occupied molecular orbital energy), ELUMO
(lowest unoccupied molecular orbital energy), hardness (η),
polarizability ( ), total negative charges on atoms (TNC),
molecular volume (MV) and total energy (TE) have been
calculated at the B3LYP level of theory with 6-311++G**
basis set. Consistent with experimental data, theoretical
results showed that the order of inhibition efficiency
is tryptophan (B) > tyrosine (C) > serine (A). In order to
determine the possible sites of nucleophilic and electrophilic
attacks, local reactivity has been evaluated through
Fukui indices.
