Effects of open inelastic channels in the resonant dissociative recombination of HeH+

We show that {ital ab} {ital initio} theory provides a quantitative description of resonant dissociative recombination. Using a variational method for the electronic scattering problem and a wave packet treatment of the dissociation dynamics, we obtain excellent agreement with recent absolute cross sections for dissociative recombination of {sup 3}HeH{sup +} in the 10--30 eV region. The cross section contains significant contributions from several resonance states, some of which autoionize into electronically excited states. A proper multichannel treatment of the resonances is needed to achieve quantitative agreement with experiment.