Laboratory Measurements of Carbon Monoxide Self-Quenching and Relationship to Titan’s Climate

Abstract:

The vibrational states of CO in Titan’s middle atmosphere are not in local thermodynamic equilibrium, thus non-LTE models are necessary to understand the energy balance in Titan’s atmosphere. Non-LTE models require accurate and precise knowledge of the rate coefficients for all processes by which CO exchanges energy with its surroundings, yet many of the kinetic parameters currently used in those models have large associated uncertainties. We are performing new experimental measurements of rate coefficients for some of the most important CO energy transfer mechanisms. Our approach involves a classic perturbation-relaxation technique combined with transient diode laser spectroscopy to measure relaxation rates. Here we will present our first results for this project, measurements of rates for room-temperature quenching of CO(v) by CO. The results of this work should help improve the reliability of non-LTE models of Titan’s atmosphere and ultimately help us better understand Titan’s past and present climate.