• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.99-102
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• 2003

The electronic structure of ${\beta}-MnO_2$ having impurities in the site of Mn was theoretically investigated by $DV-X_{\alpha}$ (the discrete variation $X{\alpha}$) method, which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The used cluster model was $[Mn_{14}MO_{56}]^{-52}$ (M = transient metals). Madelung potential and spin polarization were considered for more exact calculations. As results of calculations, the energy levels of all electron included in the model were obtained. The energy band gap and positions of impurity levies were discussed in association with impurity 34 orbital that seriously affect electrical properties of $MnO_2$. It was shown that the energy band gap decreased with the increase of the atomic number of transient metal impurity.

• Bulletin of the Korean Chemical Society
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• v.3 no.3
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• pp.98-103
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• 1982

Extended Huckel calculations have been performed to obtain molecular orbital energies and the corresponding eigenvectors for $[M(III)O_3S_3]$ type complexes [M(111) = V(111), Cr(III), Mn(III), Fe(III) and Co(III)] adopting the valence basis set orbital $(nP_z)$ and the hybridized atomic orbital of ligands. The effects of the hybridized atomic orbital of ligands on the calculated dipole moments and 10 $D_q$ values are investigated. The calculated 10 $D_q$ values and dipole moments are close to the experimental values when the hybridized atomic orbital of ligands is used to obtain the eigenvector for $[M(III)O_3S_3]$ type complexes.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1177-1184
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• 2005

Ab initio quantum chemical molecular orbital calculations have been performed for the unimolecular decomposition of methacrylonitrile ($CH_3C(CN)=CH_2$), especially for HCN and $H_2$ molecular elimination channels. Structures and energies of the reactants, products, and relevant species along the individual reaction pathways were determined by MP2 gradient optimization and MP4 single point energy calculations. Direct four-center elimination of HCN and three-center elimination of H2 channels were identified. In addition, H or CN migration followed by HCN or H2 elimination channels via the methylcyanoethylidene intermediate was also identified. Unlike the case of crotonitrile previously studied, in which the dominant decomposition process was the direct three-center elimination of HCN, the most important reaction pathway should be the direct threecenter elimination of $H_2$ in the case of methacrylonitrile.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.195-200
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• 2012

In this study we present a new approach for computing the partial atomic charge derived from the wavefunctions of molecules. This charge, which we call the "y_charge", was calculated by taking into account the energy level and orbital populations in each molecular orbital (MO). The charge calculations were performed in the software, which was developed by us, developed using the C# programming language. Partial atomic charges cannot be calculated directly from quantum mechanics. According to a partitioning function, the electron density of constituent molecular atoms depends on the electrostatic attraction field of the nucleus. Taking into account the Boltzmann population of each MO as a function of its energy and temperature we obtain a formula of partial charges.

• Textile Coloration and Finishing
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• v.21 no.5
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• pp.35-40
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• 2009

Computational calculations of molecular orbital and electrochemical redox/oxidation potentials are of very importance to determine the compound properties. The energy levels of molecular orbital were calculated by the density function theory (DFT) with exchange correction functional of local density approximation (LSA) based on the Perdew-Wang (PWC) setting and cyclic voltammetry.

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1149-1153
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• 1996

Ab initio and extended Huckel calculations were carried out on the isomers of trans-RhCl(η2-C2H2)(PH3)2 (1). Due to π-back donation in 1 complex, the rotational energy barrier of alkyne ligand is computed to be in the range of 18.6-25.2 kcal/mol at MP4 levels. The optimized hydrido-alkynyl complex (2) at ab initio level has the distorted trigonal bipyramidal structure. Vinylidene complex (3) is computed to be more stable than 1 complex by 17.1 kcal/mol at MP4//MP2 level. The stabilities of isomers show similar trend at the various level calculations, that is, EHT, MP4//HF, and MP4//MP2 levels. The optimized geometries at ab initio level are in reasonable agreement with experimental data. A detailed account of the bonding in each isomers (1-3) have been carried out in terms of orbital analyses.

• Bulletin of the Korean Chemical Society
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• v.7 no.5
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• pp.380-384
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• 1986

The infrared intensities of $CH_{4}$ and $CD_{4}$ are analyzed. The experimental dipole moment derivatives thus obtained are compared with corresponding values from the molecular orbital calculations. The theoretical results are analyzed for the charge-charge flux-overlap(CCFO) electronic contributions to the dipole derivatives.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.328-331
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• 1991

Fully optimized MNDO molecular orbital calculations are performed for N-nitroso-azirine (Ⅰ) and-diaziridine (Ⅱ). The ground state geometries show the nonplanar configuration around the imino nitrogen. The nitroso group rotational energy barriers and the ring inversion energy barriers are also discussed.

• Journal of Integrative Natural Science
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• v.15 no.4
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• pp.179-186
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• 2022

The c-Jun N-terminal kinase (JNK3) play major role in neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, cerebral ischemia and other Central Nervous System disorders. Since JNK3 is primarily stated in the brain and stimulated by stress-stimuli, this situation is conceivable that inhibiting JNK3 could be a possible treatment for the mechanisms underlying neurodegenerative diseases. In this study drugs from Zinc15 database were screened to identify the JNK3 inhibitors by Molecular docking and Density functional theory approach. Molecular docking was done by Autodock vina and the ligands were selected based on the binding affinity. Our results identified top ten novel ligands as potential inhibitors against JNK3. Molecular docking revealed that Venetoclax, Fosaprepitant and Avapritinib exhibited better binding affinity and interacting with proposed binding site residues of JNK3. Density functional theory was used to compute the values for energy gap, lowest unoccupied molecular orbital (LUMO), and highest occupied molecular orbital (HOMO). The results of Density functional theory study showed that Venetoclax, Fosaprepitant and Avapritinib serves as a lead compound for the development of JNK3 small molecule inhibitors.

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1657-1660
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• 2004

Several critical geometries associated with the rearrangement of $CH_3SNO_2\;to\;CH_3SONO$ are calculated with the density functional theory (DFT) method and compared with those of the ab initio molecular orbital methods. There are two probable pathways for this rearrangement, one involving the transition state of an oxygen migration and the other through the homolytic decomposition to radicals. The reaction barrier via the transition state is about 60 kcal/mol and the decomposition energy into radicals about 35 kcal/mol, suggesting that the reaction pathway via the homolytic cleavage to radical species is energetically favorable. Since even the homolytic cleavage requires large energies, the rearrangement reaction is unlikely without the aid of catalysts.