Knowledge Bank

The geometry of HCCN in its lowest triplet state has been studied with the restricted open shell SCF technique followed by a modest configuration interaction. The SCF results predict minima corresponding to a linear nitrene $H-C\equiv C-N$ and a bent carbene $H\setminus C-C\equiv N$ with the allylic structure $H-C¨=C=N¨$ being the transition state. In contrast, the CI results predict that the allylic structure is the only minimum on the surface.