Breakup dynamics and isotope effects in D2H and H2D dissociative recombination

The breakup dynamics of D2H + and H2D +following dissociative recombination with low energetic electrons has been studied combining two-dimensional imaging and storage ring techniques. The kinematical correlation between the hydrogen and deuterium atoms produced in the three-body channel was measured. We found that the three particles tend to dissociate with a geometry close to linear, and that the deuterium atom has a large probability to be at the center. The data also show that the remaining average internal excitation energy stored in the rotation of the D2H + and H2D + molecules corresponds to a temperature of less than 70 meV, much less than observed for the H3 + and D3 + species previously examined.