Gas Phase Studies Of Ion-Molecule Reactions Relevant to Interstellar Environments

The reactions of gas-phase ions play an important role in the formation and destruction of Complex Organic Molecules (COMs) in astrochemical environments. This thesis presents a collection of reactivity studies for ions relevant to the ionosphere of Titan and the Interstellar Medium (ISM), both to provide data for use in astrochemical models and to probe the fundamental chemistry at play. HCNH2+ and H2CNH+ are isomeric radical cations believed to contribute to the chemistry of Titan's ionosphere. Here, they have been generated through the dissociative photoionization of cyclic precursors using the DESIRS tunable VUV source at the SOLEIL synchrotron, with H2CNH+ also having been generated through the direct photoionization of the neutral. In both cases, their reactivity has been studied with a range of saturated, unsaturated, O- and N-containing organic molecules relevant to the atmosphere of Titan and the ISM. Additionally, data has been collected on the reaction of C2H5+, another ion relevant to Titan, with a series of unsaturated hydrocarbons. OCN- was the first anion to be detected in the ISM, where it has the potential to form the back-bone of a range of prebiotic species. Here, we explore the feasibility of generating OCN- using an electrospray ion source as well as presenting preliminary data on its reaction with a series of O-containing COMs of potential relevance to the ISM. He is the second most abundant species in the ISM, where it can be ionized by cosmic rays. Here, we describe the calibration of experimental parameters as well as data collected on the reaction of He+ with methanol (CH3OH), the simplest alcohol and one of the most abundant COMs in the ISM.