THE PHOTOCHEMISTRY OF OZONE

This review surveys laboratory data concerning the photochemistry of ozone, and indicates the relevance of the laboratory studies to interpretations of atmospheric chemistry. Emphasis is placed on the nature of the electronic states of the atomic and molecular oxygen fragments of photolysis, and the efficiencies with which the various species are formed. The primary quantum yield for O(**1D) formation is certainly less than unity for lambda less than 274 nm, and it may thus also be less than unity in the atmospherically critical region around lambda equals 300 nm. Similar considerations are likely to apply to the efficiency of formation of excited singlet molecular oxygen, O//2(**1 DELTA //g). On the other hand, O//2(**1 DELTA //g) seems to be formed with high efficiency at wavelengths longer than lambda approximately equals 310 nm threshold for O(**1D) production. The wavelength dependences of the quantum efficiencies are interpreted in terms of the spectroscopy of ozone. Photofragment energy analysis, coherent Raman, and fluorescence techniques have been used to probe details of the dissociation dynamics.