Photodetachment of O^- from threshold to 1.2 eV electron kinetic energy using velocity-map imaging

High-resolution photoelectron imaging from O^- with excess energies between 0.5 meV and 1.2 eV is reported. With electron energy resolutions ranging from 266 μeV to 3 meV, branching ratios and angular-distribution asymmetry parameters for each of the fine-structure transitions were measured. Preliminary data for a subset of these measurements showing possible effects due to electron correlation at low excess energy are presented, in the hope of stimulating further theoretical calculations for this species.