Temperature dependence of O(1D) quantum yields from the photolysis of ozone between 295 and 338 nm

The O(D-1) quantum yields from the photolysis of ozone (O-3) have been measured in the wavelength range 295-338 nm at temperatures of 226-298 K using chemical ionization mass spectrometry (CIMS). In the 312-324 nm range, the quantum yield was found to be temperature dependent, implying that internal energy in O-3 accounts for some of the O(D-1) production at wavelengths beyond the thermodynamic threshold of 310 nm. In the 328-338 nm range, the quantum yield is nearly constant (Phi similar to 0.12) and independent of temperature, suggesting that the "spin-forbidden" channel is active at these wavelengths and contributes to O(D-1) production beyond 310 nm. Using the quantum yields presented here results in a sizable increase in the calculated tropospheric O(D-1) production at large solar zenith angles.