Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD3OCD2+ and (CD3)2OD+
Abstract
Aims: Determination of branching fractions, cross sections and thermal rate coefficients for the dissociative recombination of CD3OCD2+ (0-0.3 eV) and (CD3)2OD+ (0-0.2 eV) at the low relative kinetic energies encountered in the interstellar medium.
Methods: The measurements were carried out using merged electron and ion beams at the CRYRING storage ring, Stockholm, Sweden.
Results: For (CD3)2OD+ we have experimentally determined the branching fraction for ejection of a single hydrogen atom in the DR process to be maximally 7% whereas 49% of the reactions involve the break up of the COC chain into two heavy fragments and 44% ruptures both C-O bonds. The DR of CD3OCD2+ is dominated by fragmentation of the COC chain into two heavy fragments. The measured thermal rate constants and cross sections are k(T) = 1.7±0.5 × 10-6(T/300)-0.77±0.01 cm3 s-1, σ = 1.2±0.4 × 10-15(Ecm[eV])-1.27±0.01 cm2 and k(T) = 1.7±0.6 × 10-6(T/300)-0.70 ± 0.02 cm3 s-1, σ = 1.7±0.6 × 10-15(Ecm[eV])-1.20±0.02 cm2 for CD3OCD2+ and (CD3)2OD+, respectively.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- May 2010
- DOI:
- 10.1051/0004-6361/200913891
- Bibcode:
- 2010A&A...514A..83H
- Keywords:
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- astrochemistry;
- molecular processes;
- plasmas;
- methods: laboratory;
- methods: numerical;
- ISM: molecules