The role of Formula and Formula ions in the degradation of interstellar molecules

The results of recent laboratory studies of the reactions of |H⁺| and |H₃⁺| with a number of molecular gases are interpreted from the viewpoint of interstellar chemistry. Many of the reactions of these ions result in the ionization and fragmentation of neutral reactant gases. Pseudo-time-dependent calculations of the chemistry in dense molecular clouds indicate that molecular abundances are reduced by the inclusion of such reactions, but generally by less than a factor of 5.