The reaction O3-+CO2⇌CO 3-+O2 has been examined in the forward and reverse directions in a variable-temperature flowing afterglow from 200 to 600 K and in a flow-drift tube at mean relative kinetic energies from 0.04 to 1 eV. The forward direction is clearly established as the exothermic direction. Furthermore, collisional dissociation of CO3- and O 3- ions in the flow-drift tube at high E/N to form O - shows that CO3- is the more stable ion. All of this implies that D(CO2+O-)> D(O2+O -). Kinetic-equilibrium studies at the higher temperatures show that the reverse rate constant is less than 6×10-15 cm3 s-1 below 600 K. When this is combined with the estimated entropy change of the reaction one obtains the quantitative lower limit D(CO 2+O-) -D(O2+O-)≥0.58 eV. The reaction OH-+O3→O3+OH is found to be fast, thereby establishing lower limits for the electron affinity of O3 and the O- bond dissociation energy of O3-. When taken with the above limit for the relative CO3- and O3- bond dissociation energy one obtains lower limits for the electron affinity of CO3 and the O- bond dissociation energy of CO3-. The latter lower limit does not overlap an upper limit for D(CO2+O-) obtained from recent photodissociation studies. The relation of this discrepancy to the electron affinity of O3 is discussed.
|Number of pages||6|
|Journal||Journal of Chemical Physics|
|State||Published - 1977|