• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.2
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• pp.33-45
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• 1995

1, 4-Diketo-3, 6-diphenyl-pyrrolo-[3, 4c]-pyrrole(abbriviated DPP) is a new heterocyclic pigment of red color whose chlorinated derivative is now on the market. DDP was synthesized from benzonitrile and diethylsuccinate. Pariser-parr-pople(PPP) molecular orbital calculations have been carried out on the DPP in other to study spectroscopically the DPP chromophore on deprotonation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.9
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• pp.711-716
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• 2012

Based on both organic synthesis and theoretical calculations on the effects of molecular orbital energy levels of amines on the fluorescence properties of the fluorophore, fluorescent "turn-on" chemosensors detecting hazardous substances, including aldehyde chemicals and $Hg^{2+}$ ion, were developed.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.422-426
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• 1990

Fully optimized MNDO molecular orbital calculations are described for N-nitroso-aziridine (I), -oxaziridine (II), and -dioxaziridine (III). The ground state geometries show the nonplanar configuration around the imino nitrogen. The nitroso group rotational energy barriers are 3.25, 0.43 and 1.18 kcal/mol for I, II and III, respectively. Also the calculated aziridine ring inversion barriers are 3.98, 15.61 and 27.46 kcal/mol for I, II and III, respectively.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.174-179
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• 1987

The results of an ab initio (6-31G) molecular orbital calculations of the dipole moment derivatives and gas phase IR intensities in $CH_3F$ and $CF_4$ are reported. The results are compared with corresponding values obtained from a CNDO calculation. We have also analyzed the theoretical polar tensors into the charge, charge flux, and overlap contributions. The effective term charges of hydrogen atom appeared to be transferable among the fluoromethane molecules.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2369-2376
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• 2007

N2O has been found from experimental and theoretical considerations to bind on-top to the Pd(110) surface in a tilted end-on fashion via its terminal N atom. We use a frontier orbital description of the bonding interactions in the Pd-N2O system to obtain molecular insight into the catalytic mechanism of the activation of N2O by the Pd(110) surface giving rise to the formation of N2 and O on the surface. For the tilted end-on N2O binding mode, the LUMO 3π of N2O has good overlap with the Pd dσ and dπ orbitals which can serve as the electron donors. The donor-acceptor orbital overlap is favorable for electron transfer from Pd to N2O and is expected to dominate the surface reaction pathway of N2O decomposition.

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.207-212
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• 2001

DFT calculations have been performed on several substituted 1,4-diaza-1,3-butadienes (1,4-DABs) with electron donating and withdrawing groups at the terminal two nitrogens to investigate the reactivity of Diels-Alder reaction with acrolein. The calculated FMO (Frontier Molecular Orbital) energies for the optimized 1,4-disubstituted-1,4-DABs have been used to explain both normal and inverse electron demand Diels-Alder reactions. It is shown that the electron donating and withdrawing substituents lead to the normal(HOMO diene controlled) and inverse electron demand (LUMO diene controlled) Diels-Alder reactions, respectively.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.3-8
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• 1985

Molecular electronegativity (EN) values are calculated employing the density functional definition of EN: the negative of the chemical potential in the density functional theory. Calculations are limited to the use of valence electrons (valence electron approximation). Our formula for the EN is given in terms of Hartree-Fock(HF) orbital energies. Resulting EN values for molecules as well as atoms exhibit a remarkable correlation with other existing scales. For molecules, we have achieved electronegativity equalization principle (Sanderson's principle).

• Bulletin of the Korean Chemical Society
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• v.5 no.1
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• pp.37-41
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• 1984

The pseudolattice calculations in the CNDO/2 level of approximation are carried out for polymeric beryllium hydride, polyethylene and polymeric boron hydride. Since there is no evidence on the geometry for polymeric boron hydride, the two possible geometries are assumed. One is a polyethylene-type geometry and the other is a polymeric beryllium hydride-type geometry. In order to compare their relative stability, we calculate polyethylene and polymeric beryllium hydride and then compare with polymeric boron hydride having the assumed structures. The total energy calculation indicates that a polymeric beryllium bydride-type geometry is more stable than a polyethylene-type geometry. Our results obtained for polyethylene are in good agreement with those given by CNDO/2 crystal orbital. From the convergence problem with respect to the number of unit cells (M), the calculation with value of 4 for M can be considered to give the convergence limit results.

• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.405-410
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• 1994

Molecular orbital calculations suggest that an interaction between the psoralen derivatives of excite state and the thymine of ground state is dicussed in terms of their differing abilities to molecular complex. PM3-CI-UHF indicates that photocycloadducts across the C3-C4 and C4'-C5' double bonds of the methylpsoralen and hydroxypsoralen with thymine C5-C6 double bonds were deduced to be formed by their preferable frontier orbital interactions. The electronic properties of psoralen derivatives in the ground and excited states correlate with this difference in structure-activity relationship.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.108-111
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• 2009

We have determined the electronic energy level alignment at the interface between 4,4'-bis-N-phenyl-1-naphthylamino biphenyl (NPB) and 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HAT-CN) using ultraviolet photoelectron spectroscopy (UPS). The highest occupied molecular orbital (HOMO) of 20 nm thick HAT-CN film was located at 3.8 eV below the Fermi level. Thus the lowest unoccupied molecular orbital (LUMO) is very close to the Fermi level. The HOMO position of NPB was only about 0.3 eV below Fermi level at NPB/HAT-CN interface. This enables an easy excitation of electrons from the NPB HOMO to the HAT-CN LUMO, creating electron-hole pairs across this organic-organic interface. We also study the interaction of HAT-CN with a few metallic surfaces including Ca, Cu, and ITO using UPS and ab-inito electronic structure calculation techniques.