Ion-molecule reactions relevant to Titan's ionosphere

Twenty four new ion-molecule reactions are presented for inclusion in the modeling of the ionosphere of Saturn's satellite Titan. Sixteen reactions were re-examined to reduce uncertainties in the previous literature results. In this study we have examined the reactions of N+ and N-2(+) with CH4, C2H2, C2H4, C2H6, HCN, CH2CHCN and HC3N; the reaction of N+ with CH3CN; the reactions of C3H3 with CH4, C2H2, C2H4, C2H6, H-2, HCN, HC3N and CH2CHCN; the reactions of C2N2+ with C2H2; C2H2+ and C2N2; C2H4 with C2H3+, C2H4+, CHCCNH+, and HC5N+; HCNH+ with C2H6; C3H6+ with C3H6; HCN with C2H6+, C3H6+, c-C3N6+ and NO+;N-2 with C2H2+ and C2H5+; C2H4+ and HC3N. The ions selected for this study were derived either from nitrogen, appropriate hydrocarbons or nitriles. The reactant neutrals were selected on the basis of their known presence in Titan's atmosphere. The reaction products are consistent with the expected increase in ion size through ion-molecule reaction processing. Data are also presented for the reactions of 23 ions with molecular nitrogen. Almost all of these ions are unreactive with N-2. (C) 1998 Elsevier Science B.V.