Ion-neutral reactions of C2H2N+ with hydrocarbons : relevant to Titan’s ionosphere

Abstract: To provide some insights on the formation of long-chain carbon-nitrogen bearing ions in Titan’s atmosphere, laboratory measurements of ion-neutral reactions were conducted and results are presented in the following licentiate thesis. The product ions of the C2H2N+ reaction with saturated and unsaturated neutral hydrocarbons have been studied using guided ion beam mass spectrometer (GIB-MS). The data have been used to infer the product ion signal intensity dependences on pressure and collision energies to obtain information on the reactions contributing to these signals. Theoretical calculations have been carried out to interpret these measurements and to elucidate the reaction pathways leading to the observed product ions. This study provides understanding on the formation of long-chain carbon-nitrogen bearing ions through exothermic and barrierless ion-neutral reactions which are of interest as possible formation routes to heavy positive ions detected in Titan’s atmosphere by Cassini’s ion neutral mass spectrometer (INMS).