• Title/Summary/Keyword: Vibrational Spectra

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A Study on the High Resolution Infrared Spectra of an Asymmetric Top Molecule $CF_2Cl_2$

  • Jung, Hyun-Chai
    • Bulletin of the Korean Chemical Society
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    • v.9 no.5
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    • pp.275-280
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    • 1988
  • The high resolution IR spectra of freon-12($CF_2Cl_2$) for the bands of 671cm$^{-1},\;922cm^{-1},\;1102cm^{-1},\;and\;1160cm^{-1}$ were taken and the rotational vibrational analysis has been carried out. The band types of $671cm^{-1}\;and\;1102cm^{-1}$ were confirmed to be A and those of $922cm^{-1}\;and\;1160cm^{-1}$ were confirmed to be B. The theoretically synthesized spectra were matched with the experimentally obtained spectra to get some informations of the molecular rotational behavior as well as the overall band shape of the spectra.

Visible Emission Sepctra of o-Xylyl Radical

  • Choe, Ik Sun;Lee, Sang Guk
    • Bulletin of the Korean Chemical Society
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    • v.16 no.3
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    • pp.281-284
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    • 1995
  • The visible emission spectra of the o-xylyl radical in the gas phase have been obtained using a Fourier transform spectrometer coupled with a technique of supersonic expansion. The o-xylyl radical was generated in a jet by expansion with an inert buffer gas He from a high voltage dc discharge of the precursor o-xylene. The spectra were analyzed on the basis of the rotational contours of the vibronic bands as well as the known vibrational frequencies by a matrix isolation method.

Raman Detection of Protein Interfacial Conformations

  • Jang, Mi-Jin;Cho, Il-Young;Callahan, Patricia
    • BMB Reports
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    • v.30 no.5
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    • pp.352-355
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    • 1997
  • The surface adsorbed protein conformations onto the vaccine adjuvants were observed with a Raman spectroscopy by using the maximum adsorption conditions described previously. The adsorbed state Raman vibrational spectra and subsequent spectral analysis display no conformational changes for BSA or IgG relative to their native species in solution.

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AKARI NEAR-INFRARED SPECTROSCOPIC SURVEY FOR COMETARY VOLATILES

  • Ootsubo, T.;Kawakita, H.;Kobayashi, H.;Usui, F.;AKARI SOSOS team, AKARI SOSOS team
    • Publications of The Korean Astronomical Society
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    • v.27 no.4
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    • pp.161-164
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    • 2012
  • We performed a spectroscopic survey for cometary volatiles with the Infrared Camera onboard the Japanese infrared satellite AKARI. The observations were carried out in the near-infrared wavelength range in the period from 2008 June to 2010 January. In this paper, we summarize the observations and results of the AKARI survey for the mixing ratios of major volatiles in comets. We derived the $2.5-5{\mu}m$ spectra of 18 comets including both Oort cloud comets and Jupiter-family comets. Prominent emission bands in the observed spectra are the fundamental vibrational bands of water ($H_2O$) at $2.7{\mu}m$ and carbon dioxide ($CO_2$) at $4.3{\mu}m$. The fundamental vibrational band of carbon monoxide (CO) at $4.7{\mu}m$ and the broad emission feature probably related to C-H bearing molecules can also be recognized around the $3.4-3.5{\mu}m$ region in some comets. We detect $CO_2$ in 17 out of 18 comets, and derived gas production rate ratios of $CO_2$ with respect to $H_2O$ in 17 comets. We detect a reliable CO emission band only in three of the comets. Our data set provides the largest homogeneous database of $CO_2/H_2O$ ratios in comets obtained so far.

mPW1PW91 Calculated and Experimental UV/IR Spectra of Unsymmetrical trans-Stilbenes

  • Choe, Jong-In;Park, Seong-Jun;Cho, Chul-Hee;Kim, Chul-Bae;Park, Kwang-Yong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.8
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    • pp.2175-2179
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    • 2010
  • Quantum mechanical properties of unsymmetrical and unfunctionalized trans-stilbene derivatives 1-3, which had been prepared by solid-phase parallel syntheses, were characterized using mPW1PW91/6-311G(d,p) (hybrid HF-DF) calculations. The total electronic energies, normal vibrational modes, Gibbs free energies, and HOMOs and LUMOs of sixteen different structures from three different groups were analyzed. The energy differences between the HOMOs and LUMOs of the various unsymmetrical trans-stilbenes are in accord with the maximum absorption peaks of the experimental UV spectra of 1-3. The calculated normal vibrational modes of 21 were comparable with its experimental IR spectrum. The $\pi$-conjugation in the para-connected biphenyl group of 2 is better than the one in the metaconnected biphenyl group on the shorter side of 3.

Preparation and Characterization of Tin(II) Complexes with Isomeric Series of Schiff Bases as Ligands

  • Refat, M. S.;Sadeek, S. A.
    • Journal of the Korean Chemical Society
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    • v.50 no.2
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    • pp.107-115
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    • 2006
  • Complexes of Sn(II) with L1 = acac-o-phdnH2 [N,N'-o-phenylene bis(acetylacetoneimine)], L2 = acac-m-phdnH2 [N,N'-m-phenylene bis(acetylacetoneimine)] and L3 = acac-p-phdnH2 [N,N'-p-phenylene bis(acetylacetoneimine)] have been prepared and characterized by elemental analyses, vibrational, electronic spectra and thermal studies (TGA and DTA). Vibrational spectra indicated the coordination mode of imine and carbonyl oxygen for ligands giving (ONNO) that belong to C2V point group symmetry. The [Sn(L3)] complex has a maximum activation energy and [Sn(L2)] complex has a minimum activation energy.

OPTICAL SPECTROSCOPY AND LIGAND FIELD PARAMETERS OF CIS-DIBROMO(1,4,8,11-TETRAAZACYCLOTETRADECANE) CHROMIUM(III) BROMIDE

  • Choi, Jong-Ha
    • Journal of Photoscience
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    • v.4 no.3
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    • pp.121-125
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    • 1997
  • The 77 K emission and excitation, and room-temperature visible spectra of cis[Cr(cyclam)Br$_2$]Br (cyclam=1,4,8,11-tetraazacyclotetradecane) are reported. The mid- and far-infrared spectra at room-temperature 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. It is found that nitrogen atoms of the cyclam ligand have strong $\sigma$-donor characters, but bromide ligand has weak $\sigma$- and $\pi$-donor properties toward chromium(III) ion. The zerophonon line in the excitation spectrum splits into two components by 172 cm$^{2-}$, and the large $^2E_g$ splitting can be reproduced by the ligand field theory.

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Growth and Characteristic Infrared Raman Spectra of Potassium Lithium Niobate Single Crystals

  • Youbao Wan;Yoo, Sang-Im
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2002.11a
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    • pp.15-15
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    • 2002
  • Homogeneous and crack-free potassium lithium niobate (K₃Li/sub 2-x/Nb/sub 5+x/O/sub 15/, 0<x<0.5, KLN) single crystals were successfully grown by the Czochralski technique. The KLN single crystals of several different compositions were employed for the investigation of the lattice vibration spectra using infrared Raman spectroscopy. The characteristic Raman spectra of the [NbO/sub 6/]/sup 7-/ octahedral ions were strikingly influenced by the Li ion content. The symmetric stretch vibrational modes V₁, V₂ are broadened, and the symmetric bend vibration mode V/sub 5/ is broadened and even split into three peaks with increasing the Li content, supporting that the bend vibration modes of the [NbO/sub 6/]/sup 7-/ octahedrons are obviously perturbed by Li ions in the C site. Enhanced Raman peak intensities after the post annealing at 900℃ and for 24 h evidenced that a residual stress in as-grown crystals was negligible and only a defect concentration might be reduced.

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Electronic Spectroscopy and Ligand Field Analysis of mer-[Cr(progly)(2,2-tri)]$CIO_4$

  • Park, Jong-Ha
    • Journal of Photoscience
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    • v.9 no.3
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    • pp.51-55
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    • 2002
  • The 77 K emission and excitation spectra, and 298 K infrared and absorption spectra of [Cr(progly)(2,2-tri)]CIO$_4$[progly=prolylglycinate,2,2-tri=N-(2-aminoethyl)-1,2-ethanediamine] have been measured. The vibrational intervals of the electronic ground state are extracted from emission and infrared spectra. The twelve electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using the observed electronic transitions, a ligand field analysis was performed to determine the metaligand bonding properties for the coordinated atoms. It is found that the carboxylate oxygen of the progly is a strong $\sigma$-and $\pi$-donor while the peptide nitrogen has weak $\pi$-donor property toward chromium(III) ion.

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Spectroscopic Properties and Ligand Field Analysis of Pentaammine(imidazole)chromium(III) Perchlorate

  • 최종하
    • Bulletin of the Korean Chemical Society
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    • v.20 no.1
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    • pp.81-84
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    • 1999
  • The emission and excitation spectra of [Cr(NH3)5(imH)](ClO4)3·H2O (imH=imidazole) taken at 77 K are reported. The 298 K visible 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. Using the observed transitions, a ligand field analysis has been performed to determine the bonding properties of coordinated imidazole in the title chromium(Ⅲ) complex. It is confirmed that nitrogen atom of the imidazole ligand has a medium it-acceptor property toward chromium(Ⅲ) ion. The zero-phonon line in the excitation spectrum splits into two components by 181 cm-1, and the large 2Eg splitting can be reproduced by the ligand field theory.