PHOTODISSOCIATION OF O2 AND CO2 FROM VIBRATIONALLY EXCITED-STATES AT HIGH-TEMPERATURES

Concentrations of O(3P) produced in the photodissociation of O2 (excited by ArF and KrF lasers) and of CO2 (ArF laser) were measured by using atomic resonance absorption spectroscopy behind reflected shock waves over 1600-2500 and 1500-2700 K temperature ranges, respectively. The Arrhenius temperature coefficients for the yield of O atoms were E(A) = 30.9 +/- 2.6 kcal/mol for photolysis of O2 excited at 248 nm, and E(A) = 13.6 +/- 3.8 kcal/mol for CO2 excited at 193 nm. The observed yield of O atoms and its time dependence in the photolysis of O2 were found to agree very well with the calculation based on the RKR potentials for the transition, B 3-SIGMA-u- <-- X 3-SIGMA-g-; it was concluded that the temperature dependence of the yield approximately represented population of the vibrationally excited states of energy E(v) almost-equal-to E(A).