DISSOCIATIVE RECOMBINATION OF PROTONATED PROPIONITRILE, CH₃CH₂CNH⁺: IMPLICATIONS FOR TITAN'S UPPER ATMOSPHERE

Abstract

The dissociative recombination of protonated propionitrile, CH3CH2CNH+, has been investigated at the heavy ion storage ring, CRYRING, at the Manne Siegbahn Laboratory, Stockholm University, Sweden. The thermal rate coefficient has been deduced to follow k(T) = (1.5 ± 0.2) × 10−6 (T/300)−0.76 ± 0.02 cm3 s−1 for electron temperatures ranging from ∼10 to ∼1000 K. Measurements of the branching fractions were performed at ∼0 eV relative kinetic energy. It has been found that in 43% ± 2% of the reactions the four heavy atoms remain in the same product fragment. An equal portion of the reactions leads to products where one of the heavy atoms is split off from the other three and 14% ± 1% result in a breakup into two heavy fragments containing two heavy atoms each. We discuss the significance of the data to Titan's upper atmosphere.