THE IR SPECTRUM OF ACETYLENE: APPLICATION TO MOLECULAR ASTRONOMY

Author Institution: NASA/Goddard Space Flight Center, Laboratory for Extraterrestrial PhysicsAcetylene is known to be a constitutent in planetary atmospheres and in the atmospheres of cool carbon stars based on spectra in the 12- to 14-micron region. From ground-based heterodyne observations of the carbon star IRC+10216 one can determine mass loss and velocity structure from these high resolution data (5 MHz, 0.3 Km/sec). A systematic laboratory study has been undertaken to interpret these astrophysical data on a quantitative basis. Spectra have been recorded with the one-meter FTS located at the McMath Solar telescope at the National Solar Observatory. The FTS was used in the double-pass mode to produce an unapodized spectral resolution of $0.0025 cm^{-1}$. We will present our current interpretation of these data. GSCO analysis has resulted in refinement of the ground state, the fundamental bending modes, and the associated hot and hot-hot bands. We have also begun an analysis of the regional intensity and will discuss progress