O 1D quantum yields from O3 photolysis in the near UV region between 305 and 375 nm

The formation of O D-1 from the photolysis of ozone has been observed at photolysis wavelengths between 305 and 375 nm and relative quantum yields for O D-1 production have been determined. Ozone was photolyzed using a frequency doubled, optical parametric oscillator. O D-1 was monitored indirectly, using laser induced fluorescence (LIF) detection of vibrationally excited OH as a "spectroscopic marker''. Relative O D-1 yields were measured from 305 to 375 nm at 295 K and from 305 to 340 nm at 273 K. The quantum yield decreases between 305 and 325 nm with a temperature dependence in the range between 310 and 325 nm. This is consistent with O D-1 production via both spin-allowed and spin-forbidden processes. Between 325 and 375 nm a constant quantum yield of 0.064 +/- 0.006 was obtained suggesting production via an exclusively spin-forbidden process and indicating that absorption takes place to a single excited state which either predissociates, yielding O P-3 and O-2 (3)Sigma(-), or crosses to another surface before dissociating to produce O D-1 and O-2 (3)Sigma(-).