Lawrence Berkeley National Laboratory

The dynamics of dissociative electron attachment to ethanol is experimentally investigated at the Feshbach resonance formed with incident electron energies near 9.5 eV. Highly differential laboratory-frame momentum distributions of OH- fragments are measured for a series of energies spanning the resonance width, using the velocity-map-imaging technique. The OH- kinetic-energy distribution indicates that the C-O breaking dissociation process could either be a three-body dissociation or a two-body dissociation with significant rovibrational excited fragments. The small, but significant, anisotropy in the OH- angular distribution provides signatures of the molecular symmetry of the associated resonant state under the axial recoil approximation, which assumes the dissociation is much faster than any rotation of the dissociation axis. Within these assumptions, the 9.5-eV Feshbach resonance can be assigned to the electronic transition from the (10a′) orbital with its ground-state Cs symmetry to the empty (4a″) level, involving the simultaneous electron attachment. This dynamics could be a model for C-O dissociation in larger alcohols and ethers.