Spectroscopic characteristics, stability, reactivity, and corrosion inhibition of AHPE-dop compounds incorporating (B, Fe, Ga, Ti): A DFT investigation

This study employs density functional theory (DFT) approach with Gaussian-09 W and Gauss view-05 programs, utilizing the DFT/B3LYP level of theory (method) /6–31(d, p) basis set, to assess the stability and reactivity of chemical compounds which include AHPE-dop-B, AHPE-dop-Fe, AHPE-dop-Ga, and AHPE-dop-Ti. Frontier molecular orbital (FMO) analysis is conducted to determine the energies of HOMO, LUMO, and their energy gap. Various molecular properties, including ELUMO, EHOMO, total energy ΔE, electronegativity (χ), hardness (η), softness (σ), electrophilicity index (ω), nucleophilicity index (ε), chemical potential (Pi), and dipole moment (μ) are explored. Neutrality is elucidated through ionization energy (IE) and electron affinity (EA). The band gap energy (Egap) is determined to comprehend chemical hardness. Thermochemical and optical properties and explanations of potential energy map theory, Fukui function, non-covalent interactions (NCI), electrostatic potential (ESP) map, and the RDG approach are explored. Using gas-phase Monte Carlo simulations, the study investigated chemical adsorption energy on Fe (110) metal surfaces. The optimized structures of AHPE-dop-B, AHPE-dop-Fe, AHPE-dop-Ga, and AHPE-dop-Ti, with ground state energies of −692.85, −1931.25, −2590.67, and −1517.11au, respectively, demonstrate the stability and energetics of these compounds. The study analyzes FT-IR bands for the mentioned elements, focusing on vibrational modes. The shifts in IR spectra reveal peaks corresponding to C-H stretching, C-H2 bending, and C-C vibrational bands. The vibrational stretching modes of O-H, N-H2, and benzene rings are also explored. Additionally, Raman spectroscopy is employed to characterize (AHPE-dop-B, AHPE-dop-Fe, AHPE-dop-Ga, and AHPE-dop-Ti) molecules, revealing shifts in peak locations due to changes in vibrational modes influenced by atomic masses and electrical configurations of the elements.