15min:

MATHIAS HAMBERG, Roslagstullsbacken 5:310 ZIP 114 21 Stockholm Sweden.

Reactions with the methoxy radical CH₃O⁺ have found to be significant pathways of production and destruction of important interstellar molecules and ions like NH₄⁺, NH₃, H₂O, H₃O⁺ . These processes compete with the dissociative recombination of the named ions. Therefore, measurements of the rates, cross-sections and branching ratios of the dissociative recombination of the iosotopomers CH₃O⁺ and CD₃O⁺ have been perfomed at the CRYRING storage ring located at Stockholm, Sweden.

Preliminary evaluation of the data yielded a reaction rate coefficient of 6.8 10^-7\left( \fracT300\right) ^-0.63 cm³mol^-1s ^-1 and 8.4 10^-7\left( \fracT300\right) ^-0.62 cm³ mol^-1s^-1 for CH₃O⁺ and CD₃O⁺, respectively. Calculation of the branching ratios rendered the following branching ratios for the reaction channels leading to the fissure of the C-O bond:, H₂O+CH (0.7%), CH₂+OH (1.6%); D₂O+CD (2%), CD₂+OD (6%) respectively. The rest of the dissociative recombination rates was contributed from channels leaving the C-O bond intact: 92% and 98% for CH₃O⁺ and CD₃O⁺, respectively. Contrary to the CH₃OH₂⁺ ion, the pathways preserving the bond between the heavy atoms dominate.