A technique for high resoln. anion photodetachment spectroscopy is presented that combines velocity map imaging and anion threshold photodetachment. This method, slow electron velocity-map imaging, provides spectral line widths of better than 1 meV. Spectra over a substantial range of electron kinetic energies are recorded in a single image, providing a dramatic redn. of data acquisition time compared to other techniques with comparable resoln. We apply this technique to at. iodine and the van der Waals cluster I.CO2 as test systems, and then to the pre-reactive Cl.D2 complex where partially resolved structure assigned to hindered rotor motion is obsd. [on SciFinder (R)]