The photoexcitation of cold oxyallyl anions was studied below the adiabatic detachment threshold at a photon energy of 1.60 eV. Photodetachment was observed through two product channels, delayed electron emission from a long-lived anionic state and dissociative photodetachment via absorption of a second photon. The former produced stable neutral C 3 H 4 O, while the latter resulted in the concerted elimination of CO+C 2 H 4 products. The neutral oxyallyl singlet state has a barrier-free route to cyclopropanone as well as zwitterionic character with a large charge separation and dipole moment. The role of long-lived dipole-bound resonances built on the singlet state below the detachment threshold is discussed. These results provide one of the first observations of delayed photoemission in a small cold molecular radical anion, a consequence of the complex electronic structure of the neutral diradical, and provide an example of resonance-mediated control of the photodissociation processes.
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- delayed photoemission
- dipole-bound states
- molecular dynamics
- photoelectron spectroscopy