The interaction of carbon monoxide with model astrophysical surfaces.

Carbon monoxide (CO) is an important component of the icy mantles that accrete on interstellar dust grains. To develop a better understanding of the physicochemical basis of its infrared spectroscopy, we have studied the interaction of submonolayer coverages of CO with the surface of films of other astrophysically relevant species--(13)CO, carbon dioxide (CO2), ammonia (NH3), methanol (CH3OH) and water (H2O)--under ultrahigh vacuum and cryogenic (10 K) conditions using reflection-absorption infrared spectroscopy (RAIRS). In support of these measurements, we have performed ab initio calculations of gas phase dimer complexes, and made comparisons to experimental results of gas phase and matrix isolated complexes, which are extensively reported in the literature.

The profile of the 2140 cm(-1) solid CO band on different substrates.

We have studied the profile of the 2140 cm(-1) fundamental band of solid carbon monoxide (CO) at low temperature (10-15 K) by infrared transmission spectroscopy and by reflection absorption infrared (RAIR) spectroscopy. In particular, transmission spectra have been taken after CO had been adsorbed on a bare crystalline silicon substrate and on pre-adsorbed solid N(2) layers of different thickness. RAIR spectra have been taken after CO had been adsorbed on a bare gold substrate and on pre-adsorbed solid N(2) layers of different thickness.