Theoretical study of the reaction of CN with C2H2+

A theoretical study of the reaction of CN with C2H2+ has been carried out a t three levels of theory, namely G2, B3LYP and CCSD(T). The main conclusion is that this is a feasible process under interstellar conditions. but only linear species may be produced. The most favourable product is HCCCN+, fol lowed by CCCNH+. Production of HCCNC+ is predicted to be slightly endotherm ic; therefore, the reaction of CN + C2H2+ may produce precursors of HC3N an d C3N in space. Furthermore, the B3LYP level is found to perform rather wel l compared with G2 and even better than CCSD(T).