TORSIONAL SPLITTINGS AND ASSIGNMENTS OF THE DOPPLER-LIMITED SPECTRUM OF ETHANE IN THE C-H STRETCHING REGION.

Abstract

The Doppler-limited absorption spectrum of the C-H stretching region of ethane has been recorded at T approximately equals 119 K with a tunable difference-frequency laser spectrometer. The strong torsional hot band structure at room temperature is eliminated at 119 K, and the enhanced resolution from the Doppler width reduction allows us to observe small torsional splittings. The two fundamentals in the region, upsilon //7, a perpendicular band and, upsilon //5, a parallel band have been essentially completely assigned as have a large number of transitions in the parallel component of the upsilon //8 plus upsilon //1//1 combination band. A number of perturbations of both global and local nature have been observed. The complete spectrum and a listing of transition wavenumbers, intensities and assignments are presented to facilitate identification and quantitative analysis of ethane in a variety of monitoring applications.