Collision-induced state-changing rate coefficients for cyanogen backbones NCN Σ and CNN Σ in astrophysical environments.

We report quantum calculations involving the dynamics of rotational energy-transfer processes, by collision with He atoms in interstellar environments, of the title molecular species which share the presence of the CN backbone and are considered of importance in those environments. The latter structural feature is taken to be especially relevant for prebiotic chemistry and for its possible role in the processing of the heterocyclic rings of RNA and DNA nucleobases in the interstellar space. We carry out calculations of their interaction potentials with He atoms and further obtain the state-to-state rotationally inelastic cross sections and rate coefficients over the relevant range of temperatures.

The CHΣ Anion: Inelastic Rate Coefficients from Collisions with He at Interstellar Conditions.

We present accurate calculations on several properties of a gas-phase system of interest in the interstellar medium (ISM), where the title molecular anion has been often surmised but not yet confirmed by observations. The CHΣ constitutes the smallest term in the series of longer anionic polyynes which have been observed in the ISM (e.g.