2,5-Bis(4-dimethylaminophenyl)-1,3,4-oxadiazole (DAPO), 2-acetylthiophene thiosemicarbazone (2-AT), 2-hydroxyphenyl-5-mercapto-1-oxa-3,4-diazole (HMO), and 2-cinnamyl-5-mercapto-1-oxa-3,4-diazole (CMO) have been studied by measurement several quantum chemical parameters such as E _HOMO, E _LUMO, bandgap energy, softness, hardness, electrophilicity, nucleophilicity, and Fukui function analysis. The best corrosion inhibition efficiency was evaluated through a comparison between theoretical and experimental results. In gas and aqueous phases, protonated and nonprotonated species were investigated for their electronic structures in order to discover the factors and reasons behind corrosion inhibition. A theoretical study of all the studied compounds in gas and aqueous phases was investigated by employing the density functional theory (DFT) at 6–311++G(d, p) basis set and Becke’s three parameters hybrid exchange–correlation functional (B3LYP). The molecules are calculated using quantum computational chemistry calculations such as Gaussian09 software. The experiments were carried out on carbon steel and HCL. Carbon steel is the most often used steel because it combines outstanding mechanical qualities with a low cost. One of the most commonly utilized agents for these purposes is HCl solution. On the other hand, steel and ferrous alloys are likely to corrode under certain conditions. One of the most effective strategies for protecting metals against corrosion is corrosion inhibitors, and they are becoming more common.

When most or all of the atoms on a single metal surface are oxidized, corrosion takes place, causing damage to the whole surface. The effects of adsorption and corrosion inhibition on different types of functional groups were studied. A review of these inhibitors based on concentration effect was performed to establish the theoretical results. It has been investigated the effects of 5-(5-(3,5-diaminophenyl)-1,3,4-oxadiazol-2-yl)-N1,N3-di-p-tolylbenzene-1,3-diamine (BATP) on mild steel in 1 M H₂SO₄ at 30 °C, Levamisole (LMS) and 4-phenylimidazole (PIZ) on copper in 0.5 M H₂SO₄, 2-phenyl-1, 4-dihydroquinoxaline (PHQ) on carbon steel in 1.0 M HCl. Based on DFT calculations in the 6–311++G(d,p) basis set in gas and aqueous phases, several quantum chemical parameters were determined to evaluate the array of selected molecules such as HOMO, LUMO, ionization energy, bandgap energy, electronegativity, chemical potential, electrophilicity, nucleophilicity, electron transfer, back-donation energy and Fukui function analysis. The most stable low-energy adsorption configurations of the materials employed in this investigation on the Fe (110) surface were induced using Monte Carlo simulations.

Corrosion is the deterioration of materials as a consequence of reaction to their environment. The corrosion in the instruction field poses safety, environmental threat, and financial. Based on DFT at 6‑311++G basis set and B3LYP level, calculated of several quantum chemical parameters. The three amino acids serine, tryptophan, and tyrosine have been investigated in gas and aqueous phases on corrosion of carbon steel utilizing DFT as green corrosion inhibitors. The order of inhibition efficiency in this study is serine < tyrosine < tryptophan, which relies on quantum chemical behaviors such as (LUMO) lowest unoccupied molecular orbital, (HOMO) highest occupied molecular orbital, electronegativity, bandgap energy, hardness, softness, chemical reactivity, polarization, total energy interaction of molecules, ionization energy, and electron affinity. The electrophilicity and nucleophilicity has been evaluated through Fukui indices. These are significant to estimate the most active reaction region, responsible for donating and accepting electrons to form coordinate bonds for the adsorption of the non-protonated species on the iron surface.

This paper aims to evaluate the range and stopping power of alpha particles in argon gas at different pressure of 0 to 1 bar, using the alpha radiation energy. The results show that the energy of the passed alpha particles has been decreased with increasing pressure in a small vacuum chamber. It is also observed that the amount of alpha particles reaching the detector follows a decreasing behavior as the distance increases. Experimental, SRIM and theoretical results for range and stopping power are closely in a good agreement. The errors in the measured range and stopping power data results from random. Only random errors have been considered in the present analysis and were estimated from pressure measurements and the uncertainty of the gas temperature.