Quantum chemical study of organic inhibitors of corrosion and hydrogen absorption An investigation of the mechanism of bainite transformation in experimental 0.2c-1v-2mn steel An investigation of the mechanism of bainite transformation in experimental 0.2c-1v-2mn steel

Results of quantum chemical calculations of the molecules of organic inhibitors (Oin) of corrosion and hydrogen absorption by metals (particularly, p-R-C6H4-SO2-NH2 where R= F, Cl, Br, CH3) both in free state and adsorbed on cluster modeling aluminium surface containing 20 atoms of Al are compared to experimental data on efficiencies of protective action (EPA) against corrosion by this metal. Energies of boundary orbitals (HOMO, LUMO) and dipole moments of isolated molecules of Oin as well as changes of atomic charges on Oin atoms when Oin molecule adsorbed have been computed using semi-empiric MNDO quantum chemistry method. It was found that correlation coefficients between EPA and changes of electric charge on N atom [ΔQ(N)] and O atom [ΔQ(O)] due to adsorption of Oin on the metal surface are the most significant. At adsorption and eventually the protection action of Oin, the specific role of polar groups (such as hydroxile) and specific role of heteroatoms (such as N, S etc) in the framework of the concepts of molecular orbitals and donor-acceptor interaction between adsorbent and adsorbate.