Reactions of Several Hydrocarbon Ions with Atomic Hydrogen and Atomic Nitrogen

Abstract

Reactions of hydrocarbon ions with atomic hydrogen are of great importance in interstellar molecular synthesis, especially in diffusive clouds (Herbst and Klemperer, 1973). We have therefore investigated the reactions of C₂H_n ⁺,n = 2 to 6, C₃ ⁺, and C₃H₂ ⁺ions with H, and H₂, and some with D and D₂in a SIFDT (selected ion flow drift tube) at 300 K in helium buffer gas at low E/N. The rate constants for various processes involved, such as binary reactions, isotope exchange and three-body association have been determined (Hansel et al., 1989). Also investigated were reactions of C₂H_n ⁺(n = 2 to 4) and of C₃H₂ ⁺with atomic nitrogen as well as several nitrogen and sulfer bearing ions with N (Freysinger et al.). The reactions with H generally lead to a reduction of the hydrogen atoms within the ion in the form${C_i}{H_n}^ + + H \to {C_i}H_{n - 1}^ + + {H_2},$or perform fast association processes,${C_i}{H_n}^ + + H\xrightarrow{{He}}{C_i}H_{n - 1}^ + + He.$