Reaction of C3H2+ with atomic nitrogen:: A theoretical study

A theoretical study of the reaction of atomic nitrogen with the different isomers of C3H2+ (HCCCH+, CCCH2+, and c-C3H2+) has been carried out. In all cases the theoretical results suggest that the predominant channel, from both thermodynamic and kinetic arguments, should correspond to production of HCCCN+, followed by production of C2H2+ + CN In the case of the reaction with linear C3H2+, Other channels, leading to CCCNH+ and C-2 + HCNH+, are also exothermic but imply higher energy barriers, and therefore should be less favorable. Our results are in partial disagreement with the selected ion flow tube experiments at thermal energies, where only two channels, corresponding to C2H2+ + CN and C-2 + HCNH+, with branching ratios of 0.85 and 0.15, respectively, were observed. Our results suggest that the reaction of nitrogen with C3H2+ is feasible under interstellar conditions and may lead predominantly to HCCCN+. This species could be a precursor of HCCCN or CCCN, two interstellar molecules.