Electron collision with the HCN and HNC molecules using the R-matrix method

The linear isomers HCN and HNC are both well known astrophysically. Electron collision calculations are presented using a 24 target state close-coupling expansion and a variety of models. All of these confirm the presence of the previously identified (2)Pi HCN anion shape resonance, although it is found that this resonance is somewhat narrower than suggested by previous calculations. HNC is also predicted to have (2)Pi anion shape resonance at a similar energy but somewhat narrower than its HCN- counterpart. Furthermore HNC also supports two narrow Feshbach resonances of (2)Sigma(+) and (2)Delta symmetry. Results are presented for the electron impact electronic excitation of both molecules.