Infrared Spectra of Organic Molecules in Water Ice Mixtures Relevant to Comets and the ISM

M. H. Moore (NASA/Goddard Space Flight Center), R. L. Hudson (Eckerd College)

The mid-infrared spectra of about twenty different organic molecules in the condensed phase at 20 K have been measured. The infrared spectrum of each of these organics has also been measured after condensing an water-organic mixture (water:organic about 20:1) at 20 K. Typically ice films a few microns in thickness are formed by condensation of molecules from the gas phase. Many of the organics are of interest because they have been detected in the ISM, and some have also been identified in comets. Other organics were chosen as reasonable candidates for molecules in cometary ices. The data set includes aliphatic hydrocarbons, acids, alcohols, ethers, ketones, and aldehydes. These data are part of the reference set used for the identification of new species formed in irradiated ices of H2O+C2H2 and H2O+CH4 (Hudson and Moore, 1997) and in our current work on the identification and formation rates of new products in ion irradiated H2O+H2CO and H2O+CO ices. A discussion of our new results will be included.

Hudson and Moore, 1997, Icarus, 126, 233-235