Spectral Line Parameters for the ν9 Band of Ethane.

Ethane is a prominent contributor to the spectrum of Titan, particularly in the region of the ν9 band at 12 μm. A multispectrum nonlinear least squares fitting program was applied to laboratory spectra of ethane to measure accurate positions, absolute intensities, N2- and self-broadened half-width coefficients and their temperature dependences for a large number transitions. These measurements include several pQ and rQ sub-bands (and other sub-bands such as pP, rR) in the ν9 fundamental band of 12C2H6 centered near 822 cm-1. Positions and intensities were measured for 3771 transitions. N2- and self-broadened half-width coefficients were determined for over 1700 transitions while temperature dependence exponents were retrieved for over 1350 of those transitions. Of these, many measurements (mostly line positions and intensities) belong to the 12C2H6ν9+ν4-ν4 and the ν9+2ν4-2ν4 hot bands, 13C12CH6 ν9 band and unidentified transitions. Forty-three high resolution (0.0016-0.005 cm-1) infrared laboratory absorption spectra recorded at temperatures between ∼150 and 298 K were fitted simultaneously to retrieve these parameters. [ABSTRACT FROM AUTHOR]