The 12 micron band of ethane - High-resolution laboratory analysis with candidate lines for infrared heterodyne searches

Abstract

Several groups have reported emission from the v 9 band of ethane at 12 ¡im in the spectra of Jupiter, Saturn, Neptune, and Titan. This paper reports the results of a laboratory study of v 9 using both high-resolution Fourier transform and diode laser absorption spectroscopy. Approximately 2000 transitions in this band have been subjected to an analysis that includes the normal rovibrational terms as well as the higher order effects of /-doubling, /-resonance, internal rotation, and a Coriolis resonance with the 3v 4 state. A model for this band capable of reproducing observed v 9 features to better than 0.001 cm" 1 is presented. High-precision values of the primary ground-state constants have also been determined: B 0 = 0-6630279(24) cm" 1 , Do 7 = 1.0324(23) x 10" 6 cm" 1 and D 0 JK = 2.651(88) x 10" 6 cm" 1 . A list of v 9 transitions occurring near 14 C02 laser lines that are good candidates for laser heterodyne searches has been compiled. An atlas is available from the authors that includes (1) plots of the observed and simulated v 9 spectra between 750 and 900 cm" 1 and (2) a list of over 8500 calculated transitions and intensities. Subject headings: line identifications -laboratory spectra -molecular processes 1984ApJ. . .280 . . 92ID 922DAUNT ET AL. Vol. 280

Radiative forcing calculations for CH{sub 3}Br

“…A discussion of PERTCOR modeling can be found in the literature (Daunt, et al, 1984). The model Hamiltonian is consistent with that of Antilla et al (1983) and is discussed at length in Daunt et al, (1984) as well as by Blass (1987).…”

“…A discussion of PERTCOR modeling can be found in the literature (Daunt, et al, 1984). The model Hamiltonian is consistent with that of Antilla et al (1983) and is discussed at length in Daunt et al, (1984) as well as by Blass (1987). The v, and v, bands were constructed using the molecular parameters of Antilla et al (1983) including the effects of the Coriolis resonance, e -doubling and e -resonance.…”

Titan's stratospheric zonal wind, temperature, and ethane abundance a year prior to Huygens insertion

“…Initially, the ''recommended'' Huygens Science Team thermal profile [Yelle et al, 1997] and a C 2 H 6 mole fraction profile constant with height above 35 mbar were used to model spectra. Ethane line frequencies, intensities, and C 2 H 6 -N 2 pressure-broadening parameters were obtained from literature [Daunt et al, 1984;Chudamani et al, 1985;Rothman et al, 1992]. The C 2 H 6 mole fraction, scale factor and velocity are varied iteratively until the best fit to the observed spectrum is obtained (solid lines in Figure 1).…”

1995 Atmospheric Trace Molecule Spectroscopy (ATMOS) linelist

“…Daunt et al 102 had produced a prediction whose integrated strength differed by 25% from that reported by Henry et al 103 and an integrated RQ 0 strength of Goldman et al 104 The 1992 HITRAN contained the Daunt et al prediction, but for the ATMOS linelist, we have normalized the intensities to match the other two studies.…”