Radiative Association between Neutral Radicals in the Interstellar Medium: CH₃ + CH₃O

Abstract

Abstract Uncertainties in the production mechanisms of interstellar complex organic molecules call for a precise investigation of gas-phase synthetic routes for these molecules, especially at low temperatures. Here, we report a study of the gas-phase formation of dimethyl ether from the neutral radicals methyl and methoxy via the process of radiative association. This process may be important to synthesize dimethyl ether and species such as methyl formate, for which dimethyl ether is a precursor. The reaction is found to be rapid by the standards of radiative association, especially at 10 K, where its rate coefficient is calculated by two different methods to be 3 × 10 −11 or 2 × 10 −10 cm 3 s −1 ; the lower rate is calculated with a more precise theory and is likely more accurate. Insertion of this reaction into the Nautilus network is found not to explain fully the abundance of dimethyl ether in cold and prestellar cores, especially in those cores with the highest dimethyl ether abundances.