Formation and dissociation of negative ion resonances in methanol and allylalcohol

Dissociative electron attachment by methanol, different deuterated methanols, and allylalcohol is studied including an analysis of the translational excess energy release of the ionic fragments. Although the energetic threshold for negative ion formation (OH−, O−) is near 2 eV, these ions are generated in methanol only within a prominent resonance at 10.5 eV. OH− and OD− formation is characterized by hydrogen scrambling in the temporary parent ion while the formation of CH3O− (and the deuterated analog) proceeds directly (no hydrogen scrambling). Only O− is generated with considerable translational excess energy (1.0±0.2 eV). In contrast to methanol, allylalcohol captures electrons at 1.7 eV to form OH− and the enolate anion (M–H)−. This resonance is interpreted as a Π radical anion comparable to that known in ethylene.