An extensive ab-initio study of the C+NH2 and N+CH2 reactions in relation to the HCN/HNC space abundance ratios

MP4SDTQ/6-311++G(3df,3pd) and CCSD(T)/6-311++G(3df,3pd) calculations have been performed for an extensive investigation of the C+NH2 and N+CH2 processes. This study reveals that reactions on the lowest doublet surfaces are strongly exothermic with no barrier to oppose the formation of HCN and HNC in their lowest singlet electronic state, suggesting that the formation of HCN(1Σ+) and HNC(1Σ+) from, respectively, N+CH2 and C+NH2 will be efficient and rather rapid. In regard to the present results, the problem of knowing to what extent N+CH2 and C+NH2 are minor processes not affecting the HCN and HNC abundances in the interstellar clouds is posed.