• Title/Summary/Keyword: Vibrational spectrum

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Photoemission and Excitation Spectroscopy of cis-Difluoro(1,4,8,11-Tetraazacyclotetradecane) Chromium (III) Perchlorate

  • Park, Jong-Ha;Hong, Yong-Pyo;Park, Yu-Chul;Ryoo, Keon-Sang
    • Journal of Photoscience
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    • v.7 no.1
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    • pp.21-26
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    • 2000
  • The photoemission and excitation spectra of cis-[Cr(cyclam)F$_2$]ClO$_4$ (cyclam = 1,4,8,11-tetraazacy-clotetradecane) taken at 77 K are reported. The 298 K mid- and far-infrared spectra are also measured. The vibrational intervals of the electronic ground state are extracted from the far-infrared and emission spectra. The ten electronic bands due to spin-allowed and spin-forbidden transitions are assigned. The zero-phonon line In the excitation spectrum splits into two components by 169 cm$^{1}$, and the large $^2$E$_{g}$ splitting can be reproduced by the ligand field theory. According to the ligand field analysis, we can confirm that nitrogen atoms of the cyclam ligand have a strong c-donor character, and fluoride ligand also has strong $\sigma$- and $\pi$-donor properties toward chromium(III) ion.n.

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Surface Cleaning of Polyethylene Terephthalate Film with Non-equilibrium Atmospheric Discharge Plasma

  • Sung, Youl-Moon
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.2
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    • pp.79-83
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    • 2008
  • The dampness by treating the surface with polyethylene terephthalate (PET) film was measured to grasp the plasma parameters and was observed the surface condition with an atomic force microscope (AFM) to find the causes of the dampness. Also, the vibrational and rotational temperatures in the plasma were calculated after identifying the radicals within the plasma by analyzing the emission spectral with an emission spectrum. The hydrophilic properties were enhanced, by treating the surface of the PET film with non-equilibrium atmospheric discharge plasma. When the rotational temperature was 0.22 to 0.31 eV within the plasma, surface modification control could be easily carried out to surface treatment of PET film on non-equilibrium atmospheric pressure plasma.

Modelling and Sensitivity Analysis for the Performance Improvement of a Spin Coater (스핀 코너 성능향상을 위한 모델링 및 민감도 해석)

  • 권태종;채호철;한창수;정진태;안강호
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.6
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    • pp.96-102
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    • 2000
  • Spinning mechanism is generally used in coasting process on grass plates. Rebounding PR(Photo Resist) which leads to occur inferiority of coating process is caused by vibrational energy of whole coating system. In this study, the sensitivity analysis is performed to analyze and reduce vibrational terms in the spin coating system. The sensitivity analysis is bared on the numerical expression of this system. By the bond graph method. power flow of each system is represented by some basic bond graph elements. Any energy domain system is modeled using the unified elements. The modelled spin coater system is verified with power spectrum data measured by FFT analyzer. As the results of verifying model parameters and sensitivity analysis, principal factors causing vibration phenomenon are mentioned. A study on vibration method in the spin coating system is discussed.

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Molecular Dyamics Simulation and Far Infrared Measurements of $Ba_{0.6}K_{0.4}BiO_3$

  • Lee, C.Y.;Song, Ki.Y.;Sperline, R.P.
    • Korean Journal of Materials Research
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    • v.6 no.6
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    • pp.555-560
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    • 1996
  • The vibrational behavior and the molecular dynamics of the high Tc superconductor Ba0.6K0.4BiO3 have been studied experimentally and by atomistic computer simulation methods. For Ba0.6K0.4BiO3, the vibrational spectrum is dominated by oxygen ion modes from 150cm-1 to 820cm-1 including infrared absorption bands at 330, 480, 640 and 830cm-1including infrared absorption bands at 330, 480, 640 and 830cm-1at room temperature. Band assignments are discussed in relation to those bands predicted by simulations, and the infrared and Raman measurements reported in the literature.

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The out-of-plane Band Contour of Dichloroborane Molecules

  • Lee, Kuk-Haeng;Kim, Ja-Hong;Sohn, Sung-Ho;Shim, Sang-Chul
    • Bulletin of the Korean Chemical Society
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    • v.8 no.3
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    • pp.147-149
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    • 1987
  • The out-of-plane bending, vibrational-rotational FT-IR spectra of dichloroborane molecule were analyzed. The band centers are 785.992, 785.723, 647.217, and 646.997 $cm^{-1}$ and centrifugal distortion constants are $2.2{\times}10^{-6},\;5.5{\times}10^{-6},\;0.2{\times}10^{-6}$, and $0.7{\times}10^{-6}cm^{-1}$ for $H^{11}B^{35}Cl_2$, $H^{11}B^{35}Cl^{37}Cl$, $D^{11}B^{35}Cl_2$, and $D^{11}B^{35}Cl^{37}Cl$, respectively. The theoretical spectrum of $D^{11}B^{36}Cl_2$ was plotted to conform the molecular constants and the rotational constants for the first excited vibrational state of this molecule were A' = 1.165932, B' = 0.106166, and C' = 0.097229 $cm^{-1}$. The calculated spectra were in good agreement with the observed spectra.

Vibrational Analysis of Dopamine Neutral Bae based on Density Functional Force Field

  • Park, Seon Gyeong;Lee, Nam Su;Lee, Sang Ho
    • Bulletin of the Korean Chemical Society
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    • v.21 no.10
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    • pp.1035-1038
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    • 2000
  • Vibrational properties of dopamine neutral species in powder state have been studied by means of the normal mode analysis based on the force constants obtained from the density functional calculation at B3LYP level and the results of Fourier trans form Raman and infrared spectroscopic measurements. Ab initio calculation at MP2 level shows that the trans conformer of dopamine has higher electronic energy about 1.4 kcal/mol than those of the gauche+ and the gauche-conformers, and two gauche conformers have almost the same energies. Free energies calculated at HF and B3LYP levels show very similar values for three conformers within 0.3 kcal/mol. Empirical force field has been constructed from force constants of three conformers, and refined upon ex-perimental Raman spectrum of dopamine to rigorous values. The major species of dopamine neutral base in the powder state is considered a trans conformer as shown in the crystallographic study of dopamine cationic salt.

A study on the safety and human engineering for the design quality improvement of vehicle seats (차량용 시트의 설계품질 향상을 위한 안전공학 및 인간공학에 관한 연구)

  • 이장무;염영하;신승훈
    • Journal of the korean Society of Automotive Engineers
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    • v.8 no.3
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    • pp.55-67
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    • 1986
  • The safety and comfort of car seats wee studied by utilization of engineering analysis/ experiment and human engineering data. As important factors of the static seating comfort, static spring constant, body pressure distribution, driving posture were discussed. In connection with the dynamic seating comfort, vibrational characteristics of domestic car seats(natural frequencies, damping, frequency spectrum, transmission ratio)were measured and discussed. Finally, the safety of the seat was analyzed and evaluated through calculation and experiments.

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Measurement of CO Q-branch Raman Spectrum by using High Resolution Inverse Raman Spectrometer (고분해능 Inverse 라만 분광기를 이용한 CO Q-branch 라만 분광 측정)

  • 한재원
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.59-64
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    • 1989
  • Raman vibrational Q0branch spectra of pure CO are measured by using the technique of quasicw inverse Raman spectroscopy utilizing a pulsed single-frequency laser source. This approach gives enhanced sensitivity compared to earlier work which employed CW lasers, allowing extension of that work to higher accuracy, higher J states, and higher pressure. Fitting laws with pertubation theory and modified energy gap(MEG) theory are described, and the line broadening and shifting coefficients of J=0 to 24 are determined with both fitting laws.

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Vibronic Spectroscopy of Jet-Cooled Benzyl-type Radicals Produced from 2-Fluoro-4-Chlorotoluene by Corona Discharge

  • Chae, Sang Youl;Yoon, Young Wook;Lee, Sang Kuk
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3565-3569
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    • 2013
  • A home-made pinhole-type glass nozzle was employed to generate vibronically excited but jet-cooled benzyl-type radicals from precursor 2-fluoro-4-chlorotoluene with a large amount of carrier gas He, from which the visible vibronic emission spectrum was recorded with a long-path monochromator. From an analysis of the spectrum observed, it was found that two benzyl-type radicals, 2-fluorobenzyl and 2-fluoro-4-chlorobenzyl radicals, were formed from the precursor in corona discharge. The possible pathway for the production of benzyl-type radicals that can explain the spectroscopic observation is herein proposed. In addition, the electronic energy of the $D_1{\rightarrow}D_0$ transition and the vibrational mode frequencies in the $D_0$ state of the 2-fluoro-4-chlorobenzyl radical were determined for the first time.

Surface-enhanced Raman Spectroscopy of Ethephone Adsorbed on Silver Surface

  • Lee, Chul-Jae;Kim, Hee-Jin;Karim, Mohammad Rezaul;Lee, Mu-Sang
    • Bulletin of the Korean Chemical Society
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    • v.27 no.4
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    • pp.545-548
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    • 2006
  • We investigated the Surface-enhanced Raman Spectroscopy (SERS) spectrum of ethephone (2-chloroethylphosphonic acid). We observed significant signals in the ordinary Raman spectrum for solid-state ethephone as well as when it was adsorbed on a colloidal silver surface, strong vibrational signals were obtained at a very low concentration. The SERS spectra were obtained by silver colloids that were prepared by the $\gamma$-irradiation method. The influence of pH and the influence of anion $(Cl^-,\;Br^-,\;I^-)$ on the adsorption orientation were investigated. Two different adsorption mechanisms were deduced, depending on the experimental conditions. The chlorine atom or the chlorine and two oxygen atoms were adsorbed on the colloidal silver surface. Among halide ions, $Br^-$ and $I^-$ were more strongly adsorbed on the colloidal silver surfaces. As a result, the adsorption of ethephone was less effective due to their steric hinderance.