Isotopic substitution shifts in methane and vibrational band assignment in the 5560–6200 cm−1 region

Nikitin, A.V.; Михайленко, С.Н.; Morino, Isamu; Yokota, Tatsuya; Kumazawa, Ryoichi; Watanabe, Takeshi

doi:10.1016/j.jqsrt.2009.02.016

Cited by 41 publications

(35 citation statements)

References 18 publications

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“…In the present contribution, intensity measurements were performed at room temperature from absorption spectra recorded by Fourier transform spectroscopy (l = 13 and 73 m) and at 81 K by differential absorption laser spectroscopy (l = 1.4 m). By applying the two temperature method, empirical lower state energies could be systematically derived, thus extending the assignments obtained by Nikitin et al [12] on the basis of spectra at 180, 240 and 298 K with a short optical path (0.0875 m). In Fig.…”

Section: Introductionmentioning

confidence: 68%

“…In Fig. 1, we present an overview comparison of the present line lists at 81 and 296 K compared to the assignments reported by Nikitin et al [12].…”

Section: Introductionmentioning

confidence: 83%

“…It should be noted that half of the 60 sub-states are not nominally infrared active and must borrow intensity to be observed in absorption. Very recently, Nikitin et al performed a very enlightening comparative study of this polyad for both 12 CH 4 and 13 CH 4 [12]. It revealed a one-to-one correspondence between the lines of the strong bands of the two isotopologues, the 13 CH 4 bands being shifted by a constant value varying between 6 and 30 cm À1 according to the vibrational band.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, despite important experimental and theoretical efforts, a satisfactory interpretation of near infrared methane still remains elusive. For the main isotopologue, 12 CH 4 , systematic identification is only available up through the octad region at 2.3 lm (P = 3 with 8 levels and 24 sublevels) [1] and significant progress has been achieved [2] only very recently in the tetradecad region (P = 4 with 14 levels, 60 sublevels) which extends between 4900 and 6200 cm À1 . For the 13 CH 4 species, only the lower polyads up to 3200 cm À1 are satisfactorily understood [3] to the extent that observed positions and intensities can be reproduced at or close to experimental uncertainties.…”

Section: Introductionmentioning

confidence: 99%

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Determination of the low energy values of 13CH4 transitions in the 2ν3 region near 1.66μm from absorption spectra at 296 and 81K

Lyulin

Kassi

Sung

et al. 2010

Journal of Molecular Spectroscopy

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a b s t r a c tThe high resolution absorption spectra of 13 CH 4 were recorded at 81 K by differential absorption spectroscopy using a cryogenic cell and a series of distributed feed back (DFB) diode lasers and at room temperature by Fourier transform spectroscopy. The investigated spectral region corresponds to the high energy part of the 13 CH 4 tetradecad dominated by the 2m 3 overtone near 5988 cm À1 . Empirical line lists were constructed containing, respectively, 1629 13 CH 4 transitions detected at 81 K (5852-6124 cm À1 ) and 3481 features (including 85 lines of 12 CH 4 ) measured at room temperature (5850-6150 cm À1 ); the smallest measured intensities are about 3 Â 10 À26 and 4 Â 10 À25 cm/molecule at 81 and 296 K, respectively. The lower state energy values were derived for 1196 13 CH 4 transitions from the variation of the line intensities between 81 and 296 K. These transitions represent 99.2% and 84.6% of the total absorbance in the region, at 81 and 296 K, respectively. Over 400 additional weak features were measured at 81 K and could not be matched to lines observed at room temperature. The quality of the resulting empirical low energy values is demonstrated by the excellent agreement with the already-assigned transitions and the clear propensity of the empirical low J values to be close to integers. The two line lists at 81 and at 296 K provided as Supplementary material will enable future theoretical analyses of the upper 13 CH 4 tetradecad.

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Section: Introductionmentioning

confidence: 68%

“…In Fig. 1, we present an overview comparison of the present line lists at 81 and 296 K compared to the assignments reported by Nikitin et al [12].…”

Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Determination of the low energy values of 13CH4 transitions in the 2ν3 region near 1.66μm from absorption spectra at 296 and 81K

Lyulin

Kassi

Sung

et al. 2010

Journal of Molecular Spectroscopy

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show abstract

“…The calculated ( 12 CH 4 -13 CH 4 ) isotopic shifts of the 5m 4 and m 2 + 4m 4 bands being À38 cm À1 and À29 cm À1 [25], respectively, the 13 CH 4 relative contribution to the absorbance in the region, may exceed the 1.1% relative abundance of this isotopologue. In the line lists attached as Supplementary Material, the 12 CH 4 and 13 CH 4 transitions are both marked with ''H" while ''D" corresponds to the CH 3 D species.…”

Section: Identification Of the Ch 3 D Transitionsmentioning

confidence: 84%

High sensitivity absorption spectroscopy of methane at 80K in the 1.58μm transparency window: Temperature dependence and importance of the CH3D contribution

Wang

Kassi

Liu

et al. 2010

Journal of Molecular Spectroscopy

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Empirical line parameters of methane in the 1.63–1.48μm transparency window by high sensitivity Cavity Ring Down Spectroscopy

et al. 2010

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We have completed the spectral coverage of the 1.58 m transparency window of methane by high sensitivity Cavity Ring Down Spectroscopy at room temperature. The achieved sensitivity ( min~3 10-10 cm-1) allowed measuring line intensities as weak as 310-29 cm/molecule i.e. three orders of magnitude smaller than the intensity cut off of the HITRAN line list of methane. The complete list contains a total of 16223 transitions between 6165 and 6750 cm-1. Their intensity values vary over six orders of magnitude from 1.6×10-29 to 2.5×10-23 cm/molecule. By comparison with a spectrum of CH 3 D recorded separately by Fourier Transform Spectroscopy, transitions due to CH 3 D in "natural" abundance in our methane sample were identified. The relative contribution of the CH 3 D isotopologue estimated by simulation of the CH 3 D and methane spectra at low resolution has showed that the CH 3 D absorption may contribute to the absorption in the region by up to 30%.

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Isotopic substitution shifts in methane and vibrational band assignment in the 5560–6200 cm−1 region

Cited by 41 publications

References 18 publications

Determination of the low energy values of 13CH4 transitions in the 2ν3 region near 1.66μm from absorption spectra at 296 and 81K

Determination of the low energy values of 13CH4 transitions in the 2ν3 region near 1.66μm from absorption spectra at 296 and 81K

High sensitivity absorption spectroscopy of methane at 80K in the 1.58μm transparency window: Temperature dependence and importance of the CH3D contribution

Empirical line parameters of methane in the 1.63–1.48μm transparency window by high sensitivity Cavity Ring Down Spectroscopy

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