Breakup dynamics and isotope effects inD2H+andH2D+dissociative recombination

Abstract

The breakup dynamics of ${\mathrm{D}}_{2}{\mathrm{H}}^{+}$ and ${\mathrm{H}}_{2}{\mathrm{D}}^{+}$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 ${\mathrm{D}}_{2}{\mathrm{H}}^{+}$ and ${\mathrm{H}}_{2}{\mathrm{D}}^{+}$ molecules corresponds to a temperature of less than $70\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, much less than observed for the $\mathrm{H}_{3}{}^{+}$ and $\mathrm{D}_{3}{}^{+}$ species previously examined.