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

Wang, L.; Kassi, S.; Liu, A.W.; Hu, S.-M.; Campargue, A.

doi:10.1016/j.jms.2010.02.005

Cited by 55 publications

(78 citation statements)

References 24 publications

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“…For NH 3 , empirical lower state energies were also determined by Brown & Margolis [34] for unassigned lines in the 4791-5294 cm −1 region. Another method has been used recently to obtain lower state energies for near-infrared lines of CH 4 by cooling an absorption cell [35].…”

Section: Molecular Opacitiesmentioning

confidence: 99%

Molecular opacities for exoplanets

Bernath

2014

Phil. Trans. R. Soc. A.

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Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy.

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Section: Molecular Opacitiesmentioning

confidence: 99%

Molecular opacities for exoplanets

Bernath

2014

Phil. Trans. R. Soc. A.

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“…[9][10][11][12]. It was developed and extensively used to characterize the absorption spectrum of methane at low temperature in the 1.58 and 1.28 lm methane transparency windows [9][10][11][12]. Briefly, it is based on an original design (see Figure 1 of Ref.…”

Section: Measurements At Low Temperaturementioning

confidence: 99%

“…A sensitivity comparable to that achieved at room temperature (a min $ 10 À10 cm À1 ) was obtained. Coinciding temperature values (80 ± 2 K) were obtained from the Doppler profile of methane absorption lines [9,10] and the rotational intensity distribution of the 3m 2 band of CH 3 D [12]. This value of 80 ± 2 K is what we refer to as 'liquid nitrogen temperature' (LNT).…”

Section: Measurements At Low Temperaturementioning

confidence: 99%

Hyperfine structure of the transitions of 16O17O, 17O18O and 17O2 by CRDS at 80K

Kassi

Leshchishina

Gordon

et al. 2011

Chemical Physics Letters

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a b s t r a c tThe high sensitivity absorption spectrum of the a 1 D g À X 3 + À g band of 16 O 17 O, 17 O 18 O and 17 O 2 has been recorded by CW-Cavity Ring Down Spectroscopy near 1.27 lm. The spectra were obtained between7640 and 7917 cm À1 with a 17 O-enriched sample at room temperature and at 80 K. Due to the I = 5/2 nuclear spin of the 17 O atom, the nuclear hyperfine structure of the transitions could be partly resolved at low temperature. The parameter coupling of the nuclear spin to the electronic angular momentum in the a 1 D g state has been derived for the three studied isotopologues of oxygen.

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“…Rotational cooling in a supersonic jet expansion is the common approach to reduce spectral congestion and simplify rovibrational analysis [2][3][4][5][6][7][8]. Thanks to the significant vapor pressure ($ 10 Torr) available at 80 K, absorption spectra of methane cooled down to liquid nitrogen temperature were recorded in several spectral regions [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Low temperature recordings combined with room temperature data allow applying the so-called "2-Temperaturemethod" which consists of deriving lower state energy level, E emp , of a given transition from the ratio of the intensities of the corresponding line measured at two temperatures [10,15,18].…”

Section: Introductionmentioning

confidence: 99%

“…Thanks to the significant vapor pressure ($ 10 Torr) available at 80 K, absorption spectra of methane cooled down to liquid nitrogen temperature were recorded in several spectral regions [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Low temperature recordings combined with room temperature data allow applying the so-called "2-Temperaturemethod" which consists of deriving lower state energy level, E emp , of a given transition from the ratio of the intensities of the corresponding line measured at two temperatures [10,15,18]. In the recent years, we have successfully applied this approach to methane spectra recorded at 80 K and 296 K by differential laser absorption spectroscopy [14][15][16] and high sensitivity CW-Cavity Ring Down Spectroscopy [18][19][20] in the 5850-7920 cm À 1 region [23].…”

Section: Introductionmentioning

confidence: 99%