Uniform WKB Wavefunctions and Franck-Condon Factors

조웅인,유병찬,Cho Ung-In,Eu Byung Chan Korean Chemical Society 1974 대한화학회지 Vol.18 No.5

2-전향점 문제의 Uniform WKB 파동함수의 정밀도를 대응하는 수치해와 비교하고 검토한 결과 Uniform WKB 파동함수가 대단히 정밀하다는 것을 발견하였다. 그러한 파동함수의 응용의 예로서 model계에 대한 Franck-Condon 인자들을 계산하였으며 계산된 인자들의 정밀도도 역시 매우 높다는 것을 보였다. Uniform WKB파동함수를 이용하여 Franck-Condon 인자의 점근치를 검토하였으며 전환진동수에 대한 Mulliken 의 조건, $E'_{n'J'}-U'_{eff}(r_s)=E"_{n"J"}-U"_{eff}(r_s),$ 을 유도하였다. The accuracy of the uniform WKB solution for a two-turning point problem is examined in comparison with the corresponding numerical solution. It is found that the uniform WKB solution is extremely accurate. Various Franck-Condon factors for a model system are calculated as an example of applications of such approximate wavefunction. The accuracy of the factors thus calculated is very good. By using the uniform WKB wavefunctions, we have examined the asymptotic limit of the Frank-Condon factors and derived the condition for the frequencies of the transitions, $E'_{n'J'}-U'_{eff}(r_s)=E"_{n"J"}-U"_{eff}(r_s),$, which was obtained by Mulliken using physical arguments.

Domain Structure of Liguid Water According to the Theory of Intermolecular Forces

전무식,조웅인,Mu Shik Jhon,Ung In Cho Korean Chemical Society 1972 대한화학회지 Vol.16 No.3

In the past years, a number of theories have been published to elucidate the structure of liquid water. common to most of these theories is that water mainly consist of several different kinds of clusters and also hydrogen bonds in water may be bent to some degree. Recentrly, in a series of paper, Jhon and Eyring successfully explained thermodynamic, dielectric, surface and transport properites of water, assuming that it contains small domains of about 46 molecules. According to the theory, the cluster size does not change with temperature, but the cluster concentration changes. In this paper, the potential function for the hydrogen bond, the dispersion energy and dipole-dipole interaction terms. The calculated results show that the domain of nearly 46 molecules is energetically most probable, and its size is independent of temperature. And also, we evaluated the effect of angel variation of the bent hydrogen bond. In addition, the relaxation energy different for ice and water is also explained by this method.

일점전개함수에 의한 수소분자의 Force Constants 의 계산

김호징,조웅인,최석진,Kim, Ho-Jing,Choi, Ung-In,Choi, Suk-Jin 대한화학회 1970 대한화학회지 Vol.14 No.1

The quadratic and cubic force constants of hydrogen molecule are calculated by use of the one center function of Bishop. The master formula on which the computation is based was suggested by the previous work of one of the present authors. The results are in good agreement with the experimental values.

Molecular Orbital Consideration of the Conformation of Chloramphenicol

채영복,조웅인,전무식,Chae, Yung Bog,Cho Ung In,Jhon Mu Shik Korean Chemical Society 1972 대한화학회지 Vol.16 No.6

Choloramphenicol분자에는 threo 및 erythro의 conformational isomer가 있고 biological activity가 아주 상이하여 threo(-)꼴만 biological activity가 있다. extended Huckel 이론을 사용 이들 분자들의 conformation을 계산하여 상기의 차이점의 이론적 설명을 꾀하였다. Chloramphenicol molecule has an asymmetric carbon, so it has conformational isomer, namely, threo and erythro form. These two forms have great difference in biological activity, that is, only threo (-) form has biological activity. Semiempirical quantum mechanical treatments are applied to these molecules to explain the difference, using the extended Huckel theory. The theoretical predictions for the preferred conformation are in good agreement with the experimental results.

Integral Hellmann-Feynman Theorem에 의한 Polarizability의 평가

김호징,조웅인,Kim, Ho-Jing,Cho, Ung-In 대한화학회 1970 대한화학회지 Vol.14 No.1

The variational approach for the direct evaluation of the energy difference ${\Delta}$E is studied. The method is based on the differential equation corresponding to the integral Hellmann-Feynman formula. The ${\Delta}$E is given by the expectation value of the Hermitian operator which does not involve the 1/$r_{ij}$ term. Because of its variational nature of the method, the coupling problem of the differential equations which are encountered in perturbation treatment does not occur. The method is applied to the evaluation of the electric polarizabilities of the Helium isoelectronic series atoms. The result is in good agreement with the experiment. The method is compared with the recent works of Karplus et al.

The Excitability by Both Electric and Concentrative Perturbation in CSTR

배정민,조웅인 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.8

전자충격으로 수소원자가 들뜰 때의 직접산란과 교환산란

강익주,조웅인,박계태 연세대학교 대학원 1985 延世論叢 Vol.21 No.3

Abstract For electron impact excitation processes of hydrogen atom from the ground state a relationship between the direct and the exchange amplitude is obtained. Within the frame work of the distorted wave approximation, the Coulomb wave is further approximated by the corresponding plane wave, while the ground state wave function is properly parametrized. Thus both scattering amplitudes are evaluated from a single expressioon by varying parameters. The use of the generating function of the Laguerre polynomials enables us to deal with the various excitation processes via a single integrated expression for 1s→2s, 1s→2pm, 1s→3s processes. Their amplitudes and their total cross sections are obtained and compared with the previous results.

Pattern Formations with Turing and Hopf Oscillating Pattern in a Discrete Reaction-Diffusion System

이일희,조웅인,Lee, Il Hui,Jo, Ung In Korean Chemical Society 2000 Bulletin of the Korean Chemical Society Vol.21 No.12

Localized structures with fronts connecting a Turing patterns and Hopf oscillations are found in discrete reaction-diffusion system. The Chorite-Iodide-Malonic Acid (CIMA) reaction model is used for a reaction scheme. Localized structures in discrete reaction-diffusion system have more diverse and interesting features than ones in continuous system. Various localized structures can be obtained when a single perturbation is applied with variation of coupling strength of two intermediates. Roles of perturbations are not so simple that perturbations are sources of both Turing patterns and Hopf oscillating domains, and spatial distribution of them is determined by strength of a perturbation applied initially.

Model Simulation of a HF Chemical Laser and Numerical Analyses of It's Behaviors

김양미,김웅,조웅인,Yang Mee Kim,Ung Kim,Ung-In Cho Korean Chemical Society 1989 대한화학회지 Vol.33 No.2

화학 레이저 모델의 이론적 연구를 화학 반응속도론, gain 과정과 유도 방출과정을 고려하여 수행하였다. 우선 F+$H_2$비 연쇄반응 HF 화학 레이저를 진동준위가 v = 3 까지 pumping되는 것으로 생각하고 관련된 rate equation을 풀어서 출력을 산출하였다. 여기서 조화진동자를 가정한 계산과 비조화성 보정을 해준 계산결과의 비교로부터 그 차이가 거의 없음을 확인하였다. 또한 여러가지 온도와 초기농도를 택하여 산출되는 laser 축력의 변화를 검토하였다. 그리고 $H_2$+$F_2$ 연쇄반응 HF 화학 레이저에 관한 비교적 단순한 model simulation을 수행하였다. 이 계산 결과는 이미 보고된 상당히 복잡한 계산결과와 비교하여 만족할 정도이었다. Theoretical analysis of HF chemical laser models are performed through chemical reaction kinetics, gain process and stimulated emission process. A chemical laser of F+$H_2$ nonchain reaction is investigated through V-R transitions of excited HF for vibrational levels up to v = 3 and rate equations including nonchain pumping and deactivation. On this analysis, harmonic and anharmonic vibrational levels are considered separately and the results of the corresponding power calculations are showed very small difference between the two. Output powers are calculated with variation of temperature and initial concentrations of $H_2$. A HF chemical laser of $H_2$+$F_2$ chain reaction is also simulated with a premixed initial condition. Results of present model calculations are satisfactory through comparison with detailed calculations reported by others.

Synthesis and Characteristics of the Organic Layered Structure Material of $(C_4H_9NH_3)_2Fe_xPb_1-xCl_4$

정수진,인리주,오응주,조웅인,김규홍,요철현,Jeong, Su Jin,In, Ri Ju,O, Eung Ju,Jo, Ung In,Kim, Gyu Hong,Yo, Cheol Hyeon Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.7

K2NiF4-type organic-based perovskites of the (C4H9NH3)2FexPb1-xCl4 (x=0.00, 0.25, 0.50, and 0.75) system have been synthesized using a low-temperatu re solution method under a flowing argon gas. When stoichiometric butylamine, iron chloride, and lead chloride are mixed, a yellow solution are obtained from slow cooling of 90 to -10 $^{\circ}C.$ The final product is a plate-like yellow crystal. The X-ray crystallographic analysis has been carried out using XRD in the range of $5^{\circ}{\leq}$ 2${\theta}$ ${\leq}80^{\circ}.$ The local symmetry around the absorbing Pb atom of the samples has been determined by the EXAFS spectroscopic study. The crystals assign to orthorhombic system by the XRD analysis. The FT-IR spectra are analyzed in the range of 600 to 3300 cm-1 . DSC and TGA are measured to detect thermal stability between 30 and 300 $^{\circ}C.$ Two endothermic peaks are detected in all samples. The electrical conductivity has been measured using the four-probes technique for the (C4H9NH3)2FexPb1-xCl4 system in 300-460 K. Photoluminescence phenomenon was also investigated at room-temperature.