dc.creator Pine, A. S. en_US dc.creator Rinsland, C. P. en_US dc.date.accessioned 2006-06-15T19:08:33Z dc.date.available 2006-06-15T19:08:33Z dc.date.issued 1998 en_US dc.identifier 1998-TF-17 en_US dc.identifier.uri http://hdl.handle.net/1811/19067 dc.description $^{a}$ C. Rinsland et al. J. Geophys. Res. 92, 11951 (1987). $^{b}$ A. Pine and W. Lafferty, J. Res. NBS. 87, 237 (1982). $^{c}$ A. Pine and S. Stone, J. Mol. Spectrosc. 175, 21 (1996). en_US dc.description Author Institution: Alpine Technologies, 14401 Poplar Hill Road; Atmospheric Sciences Division, NASA Langley Research Center en_US dc.description.abstract The strong and sharp $^{p}Q_{3}$ subbranch of the $\nu_{7}$ band of ethane near $2976.8 cm^{-1}$ is relatively free of interfering lines of methane, water and ozone and has been utilized as the signature of ethane for atmospheric $monitoring^{a}$. This subbranch is unresolvable at the Doppler limit, even at low T $(119 K)^{b}$. However, the rotational structure and torsional splittings have been obtained by subDoppler molecular-beam $spectroscopy^{c}$, along with the air-broadening coefficients and their temperature dependence, so that the fundamental band can be well characterized, apart from a minor perturbation evident at high J. This still leaves a significant fraction of the observed structure and intensity in this region unassigned. The strong temperature dependence of this extraneous structure enables us to attribute it to torsional hot bands, which improves the quantitative estimates of atmospheric ethane. We also discuss various approximations to the ethane partition function, accounting for the highly anharmonic torsional mode, needed for the accurate scaling of the intensities over the wide range of atmospheric temperatures. en_US dc.format.extent 119173 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title THE ROLE OF TORSIONAL HOT BANDS IN MODELING ATMOSPHERIC ETHANE en_US dc.type article en_US
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