Complex absorbing potential based equation-of-motion coupled cluster method for the potential energy curve of CO2− anion

The equation-of-motion coupled cluster method employing the complex absorbing potential has been used to investigate the low energy electron scattering by CO2. We have studied the potential energy curve for the 2Πu resonance states of CO2− upon bending as well as symmetric and asymmetric stretching of the molecule. Specifically, we have stretched the C−O bond length from 1.1 Å to 1.5 Å and the bending angles are changed between 180° and 132°. Upon bending, the low energy 2Πu resonance state is split into two components, i.e., 2A1, 2B1 due to the Renner-Teller effect, which behave differently as the molecule is bent