scholarly journals Quantum Chemical Studies on the Inhibiting Effect of Bipyrazoles on Steel Corrosion in HCl

2010 ◽  
Vol 7 (2) ◽  
pp. 419-424 ◽  
Author(s):  
K. Laarej ◽  
M. Bouachrine ◽  
S. Radi ◽  
S. Kertit ◽  
B. Hammouti
Keyword(s):  
Molecular Orbital ◽  
Quantum Chemical ◽  
Density Functional ◽  
Steel Corrosion ◽  
Chemical Parameters ◽  
Quantum Chemical Parameters ◽  
Highest Occupied Molecular Orbital ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Lowest Unoccupied Molecular Orbital

Correlation of the efficacy of some bipyrazoles,N,N-bis(3,5-dimethyl-pyrazol-1-ylmethyl)-cyclohexylamine (Bip 1),N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)-ethanolamine (Bip 2),N,N-bis(3,5-dimethylpyrazol-1-ylmethyl) allylamine (Bip 3) andN,N-bis(3-carboethoxy-5-methylpyrazol-1-ylmethyl)-cyclohexylamine (Bip 4), against the corrosion of mild steel in HCl is discussed using density functional approach B3LYP/6-31G(d) calculations. The bipyrazole inhibitors exhibited the highest inhibition efficiency. The quantum chemical parameters calculated are, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), the gap energy (ΔE), the dipole moment (μ), the softness (σ) and the total energy (TE).

scholarly journals Inhibition Effect of Atenolol on Copper Corrosion in 1M HNO3: Experimental Study and DFT

2021 ◽  
pp. 1-13
Author(s):  
Ehouman Ahissan Donatien ◽  
Bamba Kafoumba ◽  
Kogbi Guy Roland ◽  
Bamba Amara ◽  
Kouakou Adjoumani Rodrigue ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Quantum Chemical ◽  
Density Functional ◽  
Energy Gap ◽  
Copper Surface ◽  
Thermodynamic Quantities ◽  
Copper Corrosion ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Lowest Unoccupied Molecular Orbital

Atenolol was examined as a copper corrosion inhibitor in 1M nitric acid solution using the mass loss technique and quantum chemical studies, based on density functional theory (DFT) at the B3LYP level with the base 6-311G (d,p). The inhibitory efficiency of the molecule increases with increasing concentration and temperature. The adsorption of the molecule on the copper surface follows the modified Langmuir model. The thermodynamic quantities of adsorption and activation were determined and discussed. The calculated quantum chemical parameters related to the inhibition efficiency are the energy of the highest occupied molecular orbital E(HOMO), the energy of the lowest unoccupied molecular orbital E(LUMO), the HOMO-LUMO energy gap, the hardness (η), softness (S), dipole moment (μ), electron affinity (A), ionization energy (I), absolute electronegativity (χ),absolute electronegativity (χ), fraction (ΔN) of electrons transferred from Atenolol to copper and electrophilicity index(ω). The local reactivity was analyzed through the condensed Fukui function and condensed softness indices to determine the nucleophilic and electrophilic attack sites. There is good agreement between the experimental and theoretical results.

scholarly journals Computational Aspects of (E)-O-Carbomethoxy Methyl Oxime Ether of 1,3-Dimethyl-2,6-Diphenylpiperidin-4-One

2019 ◽  
Vol 9 (2S2) ◽  
pp. 701-706
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Atomic Charge ◽  
Molecular Geometry ◽  
Biologically Active ◽  
Oxime Ether ◽  
Structure And Property ◽  
Highest Occupied Molecular Orbital ◽  
Computational Aspects ◽  
Lowest Unoccupied Molecular Orbital

Density Functional Theoretical (DFT) studies on the biologically active oxime ether derived from 1,3-dimethyl-2,6-diphenylpiperidin-4-one has been carried out. Various quantum chemical parameters of the molecule viz. molecular geometry, Highest Occupied Molecular Orbital – Lowest Unoccupied Molecular Orbital (HOMO–LUMO) energies, Non-Linear Optical (NLO) properties, Mulliken atomic charge distribution were obtained theoretically and compared with the single crystal data. An insight into the structure and property correlation revealed the probable behavior of the molecule studied

Computational and Experimental Study onthe Adsorption and Inhibition Effects of 1,3-Benzothiazol-6-ol on the Corrosion ofSteel X80 in Acidic Solution

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Iman Danaee ◽  
Paria Nikparsa ◽  
Mohammad Reza Khosravi-Nikou
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Acidic Solution ◽  
Energy Gap ◽  
Force Microscopy ◽  
Highest Occupied Molecular Orbital ◽  
Low Concentrations ◽  
Noise Data ◽  
Chemical Factors ◽  
Lowest Unoccupied Molecular Orbital

Abstract In this work, the adsorption and inhibition behavior of 1,3-benzothiazol-6-ol were investigated by computational and experimental techniques for steel X80 corrosion in acidic solution. The density functional theory was carried out and quantum chemical factors like the energy gap, energy of highest occupied molecular orbital, the energy of lowest unoccupied molecular orbital, the fraction of electron transferred, and Mulliken charges have been calculated. In addition, according to quantum calculation, S atom in 1,3-benzothiazol-6-ol indicated more tendency for electrophilic attack in adsorption. The main reason for high inhibition efficiencies in very low concentrations is the planar and simplicity of inhibitor structure which leads to increasing the efficiency of adsorption by functional group especially sulfur. Electrochemical frequency modulation and potentiodynamic polarization indicated that this material has excellent inhibiting features in very low concentrations. The influence of DC trend on the explanation of electrochemical noise data was evaluated by polynomial fitting and the optimum polynomial order m = 5 was obtained. Noise resistance and the inhibition efficiency was calculated and compared in different methods. The theory of shot noise in frequency domain was used to obtain the electrochemical event charge. The corroded surface of steel in the absence and existence of thiazole compound was studied by Atomic force microscopy.

The Geometric and Electronic Structures of Fen-1Si(n=2-7) Clusters

2010 ◽  
Vol 150-151 ◽  
pp. 984-987
Author(s):  
Shuai Qin Yu ◽  
Li Hua Dong ◽  
Yan Sheng Yin
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Energy Difference ◽  
Ground State Structure ◽  
Magic Numbers ◽  
Highest Occupied Molecular Orbital ◽  
Hybridization Intensity ◽  
Lowest Unoccupied Molecular Orbital ◽  
The Stability

The geometric structures and electronic properties of Si doped Fen (n=2-7) clusters have been systematically studied at the BPW91 level in density-functional theory (DFT). Calculated results show that an Si impurity does not change the ground-state structure of small iron clusters and prefers to occupy surface site bonding with iron atoms as many as possible. The second-order energy difference and the vertical ionization potential show that n=4 and 6 are magic numbers within the size range studied, but the maximum value occurs at n=4 for the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital(LUMO). It is found that the hybridization intensity between Si and Fe atoms is relevant to the stability of clusters.

Investigation of Carbon Monoxide Adsorption on Cationic Gold- Palladium Clusters

2013 ◽  
Vol 68 (10-11) ◽  
pp. 651-658 ◽  
Author(s):  
Yang-Mei Chen ◽  
Xiao-Yu Kuang ◽  
Xiao-Wei Sheng ◽  
Huai-Qian Wang ◽  
Peng Shao ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Molecular Orbital ◽  
Density Functional ◽  
Co Adsorption ◽  
Vibration Strength ◽  
Au Clusters ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Pd Clusters ◽  
Homo Lumo

Density functional calculations have been performed for the carbon monoxide molecule adsorption on AunPd+m(n+m ≤ 6) clusters. In the process of CO adsorption, small Au clusters and Pd clusters tend to be an Au atom and three Pd atoms adsorption, respectively. For the mixed Au-Pd clusters, an Au atom, a Pd atom, two atoms consisted of an Au atom and a Pd atom, two Pd atoms, and three Pd atoms adsorption structures are displayed. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps and natural bond orbital charge population are calculated. Moreover, CO adsorption energy, CO stretching frequency, and CO bond length (upon adsorption) are also analysed in detail. The results predict that the adsorption strength of Au clusters with CO and the C-O vibration strength is enhanced and reduced after doping of Pd in the AunPdmCO+ complexes, respectively

Cross-conjugation as a Motif for Organic Non-Linear Optical Molecules

2014 ◽  
Vol 1698 ◽  
Author(s):  
Meghana Rawal ◽  
Kerry Garrett ◽  
Andreas F. Tillack ◽  
Werner Kaminsky ◽  
Evgheni Jucov ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Dipole Moments ◽  
X Ray Diffraction ◽  
Conjugated Molecules ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Donor And Acceptor ◽  
Vis Spectroscopy ◽  
Lowest Unoccupied Molecular Orbital

ABSTRACTWe studied the effect of a cross-conjugated bridging group (χC) on charge-transfer in a push-pull chromophore system. The hyperpolarizability of such molecules was found to be comparable to that of a fully π-conjugated molecule (πC) with the same donor and acceptor. The cross-conjugated moiety was then applied as a pendant to a fully π-conjugated chromophore containing a tricyanopyrroline acceptor (TCP). The addition of a χC moiety did not alter the intrinsic hyperpolarizability and provides an avenue for extending and aiding πC systems. The molecules were examined by X-ray diffraction (XRD), hyper-Raleigh scattering (HRS) and UV-visible (UV-vis) spectroscopy. Experimental results were compared with the predictions of density functional theory (DFT). Cross-conjugated molecules have comparable β values, relative to πC molecules, due to reduced spatial overlap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Thus, the χC architecture could facilitate independent modification of donor and acceptor strengths while minimizing unfavorable effects on electronic transitions and dipole moments.

AB INITIO AND DFT THEORETICAL INVESTIGATIONS ON NOVEL PORPHYRIN–FULLERENE SUPRAMOLECULAR DYADS FOR PHOTOVOLTAIC DEVICES

2008 ◽  
Vol 07 (05) ◽  
pp. 1055-1069 ◽  
Author(s):  
TAPAS MANNA ◽  
SUMANTA BHATTACHARYA
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Density Functional ◽  
Conformational Stability ◽  
Density Functional Theory Calculations ◽  
Orbital State ◽  
Highest Occupied Molecular Orbital ◽  
Theoretical Investigations ◽  
Lowest Unoccupied Molecular Orbital ◽  
Porphyrin Moiety

The conformational stability and electronic structures of novel H 2-(1) and Zn-tetraphenylporphyrin–[60]fullerene (2) dyads, in which the [60]fullerene is directly linked to the tetrapyrrolic rings by ethynylenephenylene subunits, have been studied by ab initio and density functional theory calculations. From the investigation on frontier molecular orbitals, it was found that the lowest unoccupied molecular orbital state of these supramolecules is localized on the fullerene and that the highest occupied molecular orbital state is localized on the porphyrin moiety. Molecular electrostatic potential maps clearly demonstrate the electron transfer phenomena from the porphyrin moiety to the fullerene in dyads 1 and 2.

A Theoretical Study of Carbohydrates as Corrosion Inhibitors of Iron

2013 ◽  
Vol 68 (8-9) ◽  
pp. 581-586 ◽  
Author(s):  
Salim M. Khalil ◽  
Elbashir E. Ali-Shattle ◽  
Nozha M. Ali
Keyword(s):  
Density Functional ◽  
Inhibition Efficiency ◽  
Theoretical Study ◽  
Energy Gap ◽  
Chemical Parameters ◽  
Iron Corrosion ◽  
Electrophilicity Index ◽  
Functional Theory ◽  
Quantum Chemical Parameters ◽  
Highest Occupied Molecular Orbital

The inhibitive effect of fructose, glucose, lactose, maltose, and sucrose against the iron corrosion is investigated using density functional theory at the B3LYP/6-31 G level (d) to search the relation between the molecular structure and corrosion inhibition. The electronic properties such as the energy of the highest occupied molecular orbital (HOMO), the energy of lowest unoccupied orbital (LUMO), the energy gap (LUMO-HOMO), quantum chemical parameters such as hardness, softness, the fraction of the electron transferred, and the electrophilicity index are reported. The inhibition efficiency of the investigated carbohydrates follows the trend: maltose <sucrose<lactose<fructose<glucose.

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