THE ION CHEMISTRY OF HNC+/HCN+ ISOMERS - ASTROCHEMICAL IMPLICATIONS

The reactivity of HCN+ and HNC+ has recently been studied in a selected-ion flow tube. In this paper the astrophysical significance of differences in HCN+/HNC+ production and reactivity is discussed. In interstellar clouds, equal amounts of HCN+ and HNC+ are formed in the reaction of CN+ + H-2, but HCN+ and HNC+ are both rapidly depleted by reaction with H-2 to form HCNH+. Thus the differences in reactivity with species less abundant than H-2 are expected to have minimal impact upon models of interstellar chemistry. However, in extraterrestrial environments lacking substantial molecular hydrogen (such as the atmosphere of Titan), differences in reactivity with hydrocarbons may have a significant effect upon the chemistry occurring.