Calculated attachment energies (in eV) relative to the neutral ground state of C₆H₆ are given together with the molecular orbitals involved in the trapping of the extra electron. The formation of this transitory anion arises from either the shape resonance (the orbital occupied by the extra electron is plotted on a gray background) or core-excited resonances when the trapping of the colliding electron into the LUMO occurs concomitantly with the promotion of a valence electron. The arrows indicate the spin of the implicated electron (↑ up, ↓ down), and “→” shows the transition.