We have investigated the dissociative recombination (DR) of the C6D6+ and C6D7+ ions using the CRYRING heavy-ion storage ring at Stockholm University, Sweden. The dissociative recombination branching ratios were determined at minimal collision energy, showing that the DR of both ions was dominated by pathways keeping the carbon atoms together in one product. The absolute reaction cross sections for the titular ions are best fitted by σ(Ecm [eV]) = 1.3 ± 0.4 × 10-15 (Ecm [eV])−1.19 ± 0.02 cm2 (C6D6+) and σ(Ecm [eV]) = 1.1 ± 0.3 ×  10-15(Ecm [eV])−1.33 ± 0.02 cm2 (C6D7+) in the intervals 3-300 meV and 3-200 meV respectively. The thermal rate constants of the titular reactions are best described by: k(T) = 1.3 ± 0.4 × 10-6(T/300)−0.69 ± 0.02 cm3s-1 for C6D6+ and k(T) = 2.0 ± 0.6 × 10-6 (T/300)−0.83 ± 0.02 cm3s-1 for C6D7+. These expressions correlates well with earlier flowing afterglow studies on the same process.

The branching ratios of the different reaction pathways and the overall rate of the dissociative recombination of CD$_{3}$OD$_{2}^{+}$ were measured at the CRYRING storage ring located at the Manne Siegbahn Laboratory in Stockholm, Sweden. A preliminary analysis of the data yielded that formation of methanol accounts for only 6 $\pm$ 2% of the total reaction rate. Largely, dissociative recombination of CD$_{3}$OD$_{2}^{+}$ involves fragmentation of the C–O bond, the major process being the three-body break-up forming CD$_{3}$, OD and D (branching ratio 0.59). A non-negligible formation of interstellar methanol by the previously proposed mechanism is therefore very unlikely.