Reactions of O⁻ with D₂ at temperatures below 300 K

The reaction of O⁻ anions with molecular deuterium D₂ has been studied experimentally using a cryogenic 22-pole radiofrequency ion trap. Two reaction channels were observed. In the associative detachment D₂O and an electron are formed and for atom transfer formation OD⁻ + D was observed. The rate coefficients of the reactions have been determined at temperatures below 300 K. The reaction rate coefficient k ₁ of the associative detachment increases with decreasing temperature from k ₁(300 K) = 0.5 × 10⁻⁹ cm³ s⁻¹ at 300 K up to k ₁(70 K) = 1.2 × 10⁻⁹ cm³ s⁻¹ at 70 K both with 30 % overall uncertainty. (paper)