Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD3OCD and (CD3)2OD+
Department of Physics, Stockholm University, Alba Nova, 106 91 Stockholm, Sweden e-mail: firstname.lastname@example.org
2 Institute of Physics, Jan Kochanowski University, Świętokrzyska 15, 25406 Kielce, Poland
3 Manne Siegbahn Laboratory, Frescativägen 26, 114 18 Stockholm, Sweden
Accepted: 4 February 2010
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) cm3 s-1, σ = 1.2±0.4 × 10-15(Ecm[eV]) cm2 and k(T) = 1.7±0.6 × 10-6(T/300) cm3 s-1, σ = 1.7±0.6 × 10-15(Ecm[eV]) cm2 for CD3OCD2+ and (CD3)2OD+, respectively.
Key words: astrochemistry / molecular processes / plasmas / methods: laboratory / methods: numerical / ISM: molecules
© ESO, 2010