Experimental Studies of the Dissociative Recombination Processes for the C6D+ 6 and C6D+ 7 Ions

We have investigated the dissociative recombination (DR) of the C 6 D 6 + and C 6 D 7 + 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 (E cm  [eV]) = 1.3 ± 0.4 × 10 -15 (E cm  [eV]) −1.19 ± 0.02 cm 2 (C 6 D 6 + ) and σ (E cm  [eV]) = 1.1 ± 0.3 ×  10 -15 (E cm  [eV]) −1.33 ± 0.02 cm 2 (C 6 D 7 + ) 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 cm 3 s -1 for C 6 D 6 + and k(T) = 2.0 ± 0.6 × 10 -6 (T/300) −0.83 ± 0.02 cm 3 s -1 for C 6 D 7 + . These expressions correlates well with earlier flowing afterglow studies on the same process.