Isotope and Electric Field Effects in Dissociative Recombination ofD3+

The cross section for dissociative recombination of vibrationally cold ${\mathrm{D}}_{3}^{+}$ has been measured at the ion storage ring CRYRING. The rate constant at 300 K, $\ensuremath{\alpha}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}{\mathrm{cm}}^{3}{\mathrm{s}}^{\ensuremath{-}1}$, is a factor of 4.3 smaller than the corresponding value for ${\mathrm{H}}_{3}^{+}$ measured earlier in CRYRING. An electric field of 30 V/cm was introduced in the electron-ion interaction region. This had no measurable effect on the dissociative recombination cross section. This suggests that the cross sections measured in storage rings for ${\mathrm{H}}_{3}^{+}$ and its isotopic variants can be directly compared with theoretical results once such results become available.