Another look at the electron attachment to nitrous oxide

Ab initio molecular orbital calculations up to the coupled-cluster level with the aug-cc-pVQZ basis set allowed us to have a new look at the electron affinity of nitrous oxide (N₂O) resulting in a detection of a new N₂O^- entity, and thereby a novel mechanism for the dissociative electron attachment process, N₂O+e^-→N₂+O^-. Addition of an electron to the linear N₂O ground state (X ^1Σ+) leads first to an open-chain bound anion which lies 25 kJ/mol above the neutral. Upon a cyclization of the open anion with an additional energy barrier of 25 kJ/mol, a cyclic anionic species is formed which is more stable than the open isomer and lies now, at most, 3 kJ/mol above the neutral ground state (the transition structure for cyclization being 50 kJ/mol above neutral N₂O). The cyclic anionic species constitutes a weak complex between N₂ and O^- characterized by a binding energy of only 16 kJ/mol. The electronic structure of the anion complex is analyzed, a number of earlier experimental results are clarified and a resolution for the long-standing disagreement between experiment and theory around the electron affinity of N₂O is proposed.