Measurement of Branching Ratios for the Dissociative Recombination of Cold HD+ Using Fragment Imaging

Two-dimensional fragment imaging is used to determine branching ratios into final atomic states for dissociative recombination of vibrationally cold HD⁺ molecules with electrons at variable energy. For low electron energies it is found that the dissociation proceeds via the ¹Σ⁺_g state, leaving one of the fragments in the n = 2 level. At higher energies up to ~20 eV, a pronounced angular anisotropy of the fragmentation is found on one of the previously measured resonances, allowing for conclusions about the symmetry of the dissociating states.