Dissociative recombination of protonated dimer ions H+•(HCOH)2 and H+•(CH3COH)2 with electrons at near thermal energies

Formation of the protonated formaldehyde and acetaldehyde dimer ions, H+.(HCOH)(2) and H+.(CH3COH)(2), respectively, and their subsequent dissociative recombination with electrons was studied in a high-pressure flowing afterglow (HPFA) using the axially movable Langmuir probe. The obtained recombination rate coefficients are (3.3 +/- 1) x 10(-6) cm(3) s(-1) for H+.(HCOH)(2) and (1.4 +/- 0.5) X 10(-6) cm(3) s(-1) for H+.(CH3COH)(2), at 450 and 500 K, respectively. The evolution of the electron energy distribution function and the electron temperature in the recombination-dominated flowing afterglow plasma were also measured.