Momentum imaging of dissociative electron attachment to N 2 O at the 2.3-eV shape resonance

We report ion momentum imaging measurements of dissociative electron attachment to N${}_{2}$O near the well-known 2.3-eV shape resonance. We have made a comparison to previous results and have used the formalism of O'Malley and Taylor [Phys. Rev. 176, 207 (1968)] to calculate angular O${}^{\ensuremath{-}}$ anion fragment distributions. Using these angular distributions along with the axial recoil approximation, we show a predominant $\ensuremath{\Pi}$ contribution to the observed angular O${}^{\ensuremath{-}}$ distribution with no significant indication of a $\ensuremath{\Sigma}$ contribution, as previously reported. We conclude that the dissociation takes place in a near-linear geometry and proceeds across a Renner-Teller barrier.