Laboratory studies of hydrocarbon nucleation in Titan's atmosphere and the optical constants of water ice in the far-infrared

Titan, Saturn's largest satellite has a thick nitrogen/methane atmosphere. Methane, and other hydrocarbon gases formed by photochemistry in Titan's atmosphere should condense in Titan's lower stratosphere and upper troposphere. However, Titan's cloud formation mechanism is poorly understood. This thesis describes laboratory measurements of the nucleation of methane, ethane, and butane onto laboratory-produced analogs of Titan's haze particles (tholins). It is found that methane and ethane nucleation onto the tholin material requires a critical saturation ratio of Scrit = 1.05. Butane nucleation onto the tholin material requires a relatively high critical saturation ratio of Scrit = 1.30. Implications for Titan's cloud formation are discussed.; Cirrus clouds in Earth's atmosphere are composed of water ice. Water ice is also ubiquitous in the solar system. Accurate optical constants of water ice in the far-infrared are critical for satellite retrieval of the properties of water ice particles in clouds and surface ice on planetary bodies. This thesis describes a laboratory measurement of the optical constants of water ice in the far-infrared, as well as a comparison with previous results.