• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2617-2620
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• 2009

Using Coulomb-Yukawa like correlated interaction potentials of integer and noninteger indices the series expansion formulae in terms of multicenter overlap integrals of three complete orthonormal sets of ${\psi}^{\alpha}$‒exponential type orbitals and linear combination coefficients of molecular orbitals are established for the potential of electrostatic field produced by the charges of molecule, where $\alpha$ = 1, 0, ‒1, ‒2,${\cdots}$. The formulae obtained can be useful for the study of interaction between atomic--molecular systems containing any number of closed and open shells when the ${\psi}^{\alpha}$‒exponential type basis functions and Coulomb-Yukawa like correlated interaction potentials are used in the Hartree-Fock-Roothaan and explicitly correlated approximations. The final results are valid for the arbitrary values of parameters of correlated interaction potentials and orbitals. As an example of application, the calculations have been performed for the potential energy of interaction between electron and molecule $H_2O$ using combined Hartree-Fock-Roothaan equations suggested by the author.

• 통합자연과학논문집
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• 제3권4호
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• pp.231-236
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• 2010

Partial charge is an important and fundamental concept which can explain many aspects of chemistry. Since a molecule can be regarded as neclei surrounded by electron cloud, there is no way to define a partial charge accurately. Nevertheless, there have been many attempts to define these seemingly impossible parameters, since they would facilitate the understanding of molecular properties such as molecular dipole moment, solvation, hydrogen bonding, molecular spectroscopy, chemical reaction, etc. Common methods are based on the charge equalization, orbital occupancy, charge density, and electric multipole moments, and electrostatic potential fitting. Methods based on the charge equalization using electronegativity are very fast, and therefore they have been used to study many compounds. Methods to subdivide orbital occupancy using basis set conversion, relies on the notion that molecular orbitals are composed of atomic orbitals. The main idea is to reduce overlap integral between two nuclei using converted orthogonal basis sets. Using some quantum mechanical observables like electrostatic potential or charge multipole moments. Using potential grids obtained from wavefunction, partial charges can be fitted. these charges are most useful to describe intermolecular electrostatic interactions. Methods to using dipole moment and its derivatives, seems to be sensitive the level of theory, Dividing electron density using density gradient being the most rigorous theoretically among various schemes, bears best potential to describe the charge the most adequately in the future.

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.129-136
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• 1986

The dipole moments for some coordination compounds with organic ligands have been calculated adopting the molecuar orbitals obtained from EHT calculation with modified technique. Adopting the molecular orbitals with the modified technique, the calculated dipole moments for all the coordination compounds with organic ligands give closer agreements with experimental values than those using the molecular orbitals obtained from EHT calculation. The calculated dipole moments suggest that $(C_2H_5)_2SO,\;(C_6H_5)_2SO,\;and\;(C_6H_5)_2SeO$ may have a trigonal planar structure and $(C_6H_5)_3AsO,\;and\;(C_6H_5)_3PBCl_3$ a square planar structure and $(C_2H_5)_2OZrCl_4$ may be distorted markedly. This work may also indicate that the modified technique is superior to the EHT calculation as far as the dipole moment calculation is concerned.

• 대한화학회지
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• 제22권3호
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• pp.117-127
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• 1978

두점 A와 B에 위치한 Slater원자궤도함수의 spherical harmonics부와 지름부를 기준점 A를 중심으로 전개하여 공통좌표상에 기술하였다. 이 Slater 원자궤도함수의 전개식을 사용하여 two center overlap integral의 기본식을 유도하였으며 이 기본식을 이용하여 $CH_4,\;H_2O,\;NH_3,\;C_2H_6$ 및 $PH_3$ 분자의 two center overlap integral을 계산하였을 때 이 값이 Mulliken의 값과 일치하였다.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.63-71
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• 1993

By use of cluster orbitals, analytic solutions of finite face-centered cubic clusters are obtained. Taking interactions between up to the second nearest neighbors into account, the forms of all the elements of the Hamiltonian matrix are found explicitly within Huckel approximation. By adopting $D_{2k}$ point group to the cluster, the matrix is simplified. We assume that the cluster orbitals can mix together only when their state indices are indentical. It is then possible to calculate various physical properties of face-centered cubic metal clusters and example are shown for palladium clusters. The results show that density of states and projected density of states are similar, qualitatively, with those obtained by extended Huckel calculation.

• Bulletin of the Korean Chemical Society
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• 제14권5호
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• pp.578-583
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• 1993

By including the overlap integrals between atomic orbitals, the modified cluster orbitals for a metal cluster of face centered cubic lattice are found. The modified analytic solutions of the cluster are obtained from them with the assumption that the cluster orbitals with different state indices do not mix together. The physical properties-the HOMO levels and the unit electronic energies-of Ni, Pd, and Pt clusters of various size, calculated by the modified cluster orbital method, agree better with the results obtained by the Extended Huckel calculation than those of the previous(unmodified) cluster orbital method do. As a result, it is verified that the physical properties, at least those related to the energy levels, obtained by the Extended Huckel method may be reproduced by use of the modified cluster orbital method instead.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.6-13
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• 2022

The electrostatic phenomenon seriously issued in extreme ultraviolet semiconductor cleaning was studied in junction with molecular dynamic aspect. It was understood that two lone pairs of electrons in water molecule were subtly different each other in molecular orbital symmetry, existed as two states of large energy difference, and became basis for water clustering through hydron bonds. It was deduced that when hydrogen bond formed by lone pair of higher energy state was broken, two types of [H₂O]⁺ and [H₂O]^- ions would be instantaneously generated, or that lone pair of higher energy state experiencing reactions such as friction with Teflon surface could cause electrostatic generation. It was specifically observed that, in case of electrolyzed cathode water, negative electrostatic charges by electrons were overlapped with negative oxidation reduction potentials without mutual reaction. Therefore, it seemed that negative electrostatic development could be minimized in cathode water by mutual repulsion of electrons and [OH]^- ions, which would be providing excellences on extreme ultraviolet cleaning and electrostatic control as well.

• 한국재료학회지
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• 제33권6호
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• pp.236-241
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• 2023

Solar cells based on p-conjugated donor-acceptor (D-A) organic molecular systems are a promising alternative to conventional electrical energy generation. D-A molecular systems, which have a triphenylamine (TPA) moiety linked with a benzothiadiazole (BTD) moiety, open the potential development of new small molecule donors for bulk heterojunction (BHJ) solar cells. Here, a series of donor-acceptor-π-acceptor (D-A-π-A) small molecule donors (SMD) derived from triphenylamine (TPA) donor and benzothiadiazole (BTD) acceptor building blocks, were designed for BHJ organic solar cells. The small molecule donors SMD1-4 were studied using density functional theory (DFT) and time dependent-DFT (TDDFT) methods, to understand the effect of cyano and fluorine group functionalization on their properties. The effect of structure alteration by cyano and fluorine group functionalization on the optoelectronic properties, the calculated highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) and the HOMO-LUMO gaps were theoretically explored. The V_oc (open-circuit photovoltage) and fill factor (FF) for SMD1-4 were obtained with a PC₇₁BM acceptor, which showed that these organic small molecules are potential small molecule donors for organic bulk heterojunction solar cells.

• 대한화학회지
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• 제25권2호
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• pp.61-66
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• 1981

팔면체 [M(Ⅲ)$A_3B_3$]형태 착물의 쌍극자모멘트에 ${\pi}$결합 분자궤도함수의 기여분을 계산하는 방법을 발전시켰다. [M(Ⅲ) = Ti(Ⅲ), V(Ⅲ), Cr(Ⅲ), Fe(Ⅲ), 또는 Co(Ⅲ); A = O 또는 N; B = N, S 또는 Cl] 쌍극자모멘트에 대한 ${\pi}$결합 분자궤도함수의 기여분은 ${\sigma}$결합 분자궤도함수의 기여분보다 작지만 비 편재화 ${\pi}$전자를 가지고 있는 킬레이트 착물에 까지도 무시할 수 없음이 발견되었다. 계산한 쌍극자모멘트가 ${\sigma}$결합 형성 만을 가정했을 때 보다 실험치에 가까웠다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 춘계학술발표회 초록집
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• pp.73-87
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• 1996

The outer-most electrons of metal atoms and the remining valence electrons of any molecular atoms make three dimensional crystallizing $\pi$-bondings. The electrons on the $\pi$-bonding orbital rotate clockwise or counter-clockwise and they then make electro-magnetic waves between atoms on the orbital because electron move between plus charged ions. The three dimensional crystallizing $\pi$-bonding orbitals are quantum-mechanically modeled by a cyclic Kronig-Penny Model and energy band structures are analyzed with their potential barrier thickness. The waves generated between plus charged ions are the particular $\pi$-far infrared rays, which have dual properties between material and electro-magnetic waves and can be measured not by modern electro-magnetic tester but biosensor such as finger's force tester. Because the $\pi$-rays can be modulated with electro-magnetic waves it can be applied for harmful electro-magnetic wave killers. Because the $\pi$-rays make new three dimensional crystallizing $\pi$-bonding orbitals in the material the food and drink can be transformed into a helpful physical constitutional property for human health. Distinction between crystalline and amorphous metals is possible because very strong crystalline $\pi$-bonding orbitals can not easily be transformed into another. The $\pi$-rays can also be applied for biofunctional diagnostics and therapy. Gravitational field is one of the electro-magnetic fields. And also magnetic field and gravitational force field make charge's movement. ($\times$ = q, : magnetic field, : force field, q: plus charge, : velocity field)