An extensive ab initio study of a process of astrophysical interest: the N+(N)+CH3(CH3+) reaction

The impact of the N+(N)+CH3(CH3+)→NH2C++H process on the relative HNC and HCN space abundances is investigated in order to test the astrophysical hypothesis stating that, in cold interstellar clouds, this reaction may contribute to the observed HNC/HCN abundance ratio greater than unity. Our extensive ab initio study of the lowest surfaces of both doublet and quartet multiplicities shows that the HNCH+ entity is formed in its linear arrangement, the dissociative recombination of which is known to lead to an equal amount of HCN and HNC. Therefore it can be inferred that this reaction cannot account for an HNC/HCN abundance ratio larger than unity and that the above hypothesis has to be reconsidered.