The possibility of electron attachment to the valence 3Π state of CO is examined using an {\it ab initio} bound-state multireference configuration interaction approach. The resulting resonance has 4Σ− symmetry; the higher vibrational levels of this resonance state coincide with, or are nearly coincident with, levels of the parent a3Π state. Collisional relaxation to the lowest vibrational levels in hot plasma situations might yield the possibility of a long-lived CO− state.
@article{arxiv.physics/9810009,
title = {Electron attachment to valence-excited CO},
author = {Sanjay Kumar and D. Mathur},
journal= {arXiv preprint arXiv:physics/9810009},
year = {2009}
}