Temperature Dependence of O(1D) Quantum Yields from the Photolysis of Ozone between 295 and 338 nm

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The O(1D) quantum yields from the photolysis of ozone (O3) 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 O3 accounts for some of the O(1D) production at wavelengths beyond the thermodynamic threshold of 310 nm. In the 328−338 nm range, the quantum yield is nearly constant (Φ ∼ 0.12) and independent of temperature, suggesting that the “spin-forbidden” channel is active at these wavelengths and contributes to O(1D) production beyond 310 nm. Using the quantum yields presented here results in a sizable increase in the calculated tropospheric O(1D) production at large solar zenith angles.