Recombination coefficients for H3O+ ions with electrons e− and with Cl−,Br− and I− at flame temperatures 1820–2400 K

Rate coefficients were measured for gas-phase electron–ion recombination of H3O+ and for ion–ion recombination of H3O+ with Cl−,Br− and I− in five H2–O2–N2 flames spanning a temperature range 1820–2400 K. A novel, simple and accurate technique was employed involving total positive ion collection at an electrode located a variable distance downstream of the flame reaction zone; a bias voltage was applied between the collection electrode and the metallic burner. The measured values of the recombination coefficients in cm3 molecule−1 s−1 units are: (0.0132±0.0004)T−1.37±0.05 for H3O+/e−;(20.8±0.7)T−2.52±0.16 for H3O+/Cl−;(1.01±0.04)T−2.14±0.07 for H3O+/Br−; and (8.82±0.35)T−2.40±0.12 for H3O+/I−.