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 H- 2-O-2-N-2 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 reacti on zone; a bias voltage was applied between the collection electrode and th e metallic burner. The measured values of the recombination coefficients in cm(3) molecule(-1) s(-1) units are: (0.0132 +/- 0.0004)T-1.37+/-0.05 for H 3O+/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-. (C) 2000 Elsevier Science B.V. All rights reserved.