The 2B1 shape resonance in electron-formaldehyde scattering: an investigation using the dilated electron propagator method

The zeroth order, second order, diagonal two particle one hole-Tamm Dancoff approximation and the corresponding quasi-particle decouplings of the dilated electron propagator have been applied to investigate the 2B1 HCHO− shape resonance. The results from these calculations are in good agreement with the experimental and other theoretical results. The resonant orbital is shown to be the >C=O π∗ orbital and the correlation and relaxation effects in conjunction with complex scaling assist resonance formation by lowering the antibonding nature of the >C=O π∗ orbital to make it more suitable for metastable electron attachment.