Formation and Decay of (3PJ)O Atoms in the Laser Flash Photolysis of Chlorine Dioxide (OClO) at 308 nm

Article abstract of DOI:10.1021/j100389a014

The primary quantum yields of O(³P_J) and Cl(²P_3/2) atoms in the laser flash photolysis of OClO(g) at 308 nm and 298 K and the kinetics of the subsequent oxygen atom decay have been investigated by time-resolved atomic resonance fluorescence measurements.The determined quantum yields are Φ_O = 1.02 +/- 0.05 and Φ_Cl < 0.01.Second-order rate constants for the reaction between = atoms and OClO are pressure dependent with a finite intercept.The rate constant for the bimolecular channel O + OClO -> O2 + ClO (1) has a value of k₁ = (1.6 +/- 0.4) * 10^-13 cm³ molecule ^-1s^-1.Termolecular reaction rates for O + OClO + Ar -> ClO3 + Ar (2) can be fit with k₂₀ = (1.4 +/- 0.3) * 10^-31 cm⁶ molecule^-2s^-1 and k_2infinite = (3.1 +/- 0.8) * 10^-11 cm³ molecule^-1 s^-1.A value of ΔH_f(ClO3) = 55.6 +/- 4 kcal/mol is derived from k₂₀ and unimolecular reaction theory by assuming a collision efficiency of β = 0.76 for argon.