INFRARED-SPECTRA OF GASEOUS ORGANICS - APPLICATION TO THE ATMOSPHERE OF TITAN .2. INFRARED INTENSITIES AND FREQUENCIES OF C-4 ALKANENITRILES AND BENZENE

The infrared spectra of butanenitrile (n-propyl cyanide = n-PrCN), 2-methylpropanenitrile (isopropyl cyanide = i-PrCN), cyclopropanecarbonitrile (cyclopropyl cyanide = ΔCN) and benzene, in the gas phase, have been systematically studied in the 3000-250 cm-1 wavenumber region. For each of these compounds the most intense vibration bands have been determined. Their absolute intensities and the associated uncertainties have been estimated. These data were then used to derive upper limits of the mean mixing ratios of these compounds in Titan's atmosphere from a newly studied selection of IRIS i.r. spectra. The obtained upper limits are of the order of a few tenths of ppm for the studied nitriles and a few ppb for benzene. © 1990.