EXCHANGE-REACTIONS OF O-18- WITH SOME DIATOMIC AND TRIATOMIC-MOLECULES

Rate coefficients have been measured for the reactions of O-18- with H2O, CO2, O2, CO, NO and SO2 using the tandem flowing afterglow selected ion flow tube. For H2O and CO2, isotope exchange occurs at the statistical limit, which suggests the formation of a long-lived complex. In contrast, the exchange reaction with O2 occurs with only 17% efficiency. Both associative detachment and isotope exchange are observed in the reactions of O-18- with CO, NO and SO2. These data are discussed together with previous results to obtain a comprehensive picture of the reaction mechanisms.