RANDOM BAND MODELS OF THE SPECTRUM OF PROPANE FROM $690 TO 1580 cm^{-1}$

Abstract

Propane has been detected by the Voyager I IRIS investigators in the spectrum of Titan and also has been tentatively identified in the spectra of Jupiter and $Saturn^{1}$ by means of its Q branch at $748 cm^{-1}$. To assess the importance of propane as a contaminant in the identification and measurement of other features in planetary spectra, we have undertaken a laboratory study of the propane spectrum from $690 to 1580 cm^{-1}$. At room temperature spectra have been obtained with a wide range of pressures: from 40 torr to 90 pain. The data were fit to a Mayer-Goody random band model to determine the mean absorption coefficient and mean line spacing at each $2 cm^{-1}$ interval in this spectral range. Band intensities were also determined independently and compare to the intergral of the mean absorption coefficient resulting from the band model for each band. We have also obtained some spectra at 200 K at the lower pressure to investigate changes in the spectrum at the lower temperature relevant to the outer planets.