Electron-impact detachment of D^-: near-threshold behavior and the nonexistence of D^2- resonances

Abstract

D^- has been stored in the heavy-ion storage ring ASTRID and merged with the electron beam from an electron cooler. The cross section for electron-impact detachment of D^- was measured for relative energies from 0 to 20 eV. No evidence is found for the earlier reported resonances that were ascribed to short-lived H^2- states. We present a simple classical "reaction-zone" model which essentially reproduces the data except in the region close to the threshold where the cross section is small.