Dissociative recombination of the deuterated acetaldehyde ion, CD3CDO+: product branching fractions, absolute cross sections and thermal rate coefficient

Abstract

Dissociative recombination of the deuterated acetaldehyde ion CD₃CDO⁺ has been studied at the heavy-ion storage ring CRYRING, located at the Manne Siegbahn Laboratory, Stockholm, Sweden. Product branching fractions together with absolute DR cross-sections were measured. The branching fractions were determined at a relative collision energy between the ions and the electrons of ∼0 eV. With a probability of 34% the DR events resulted in no ruptures of bonds between heavy atoms (i.e. no breakage of the C–C bond or the CO bond). In the remaining 66% of the events one of the bonds between the heavy atoms was broken. The energy-dependent cross-section for the DR reaction was measured between ∼0 and 1 eV relative kinetic energy. In the energy region between 1 meV and 0.2 eV the absolute cross section could be fitted by the expression σ(E) = 6.8 × 10⁻¹⁶E^−1.28 cm², whereas in the energy interval between 0.2 and 1 eV the data were best fitted by σ(E) = 4.1 × 10⁻¹⁶E^−1.60 cm². From these cross section data the thermal rate coefficient (as a function of the electron temperature), α(T) = 9.2 × 10⁻⁷ (T/300)^−0.72 cm³ s⁻¹ was obtained.