TIME-OF-FLIGHT MEASUREMENTS OF THE KINETIC ENERGIES OF THE O-2(A(1)DELTA(G)) FRAGMENT FROM THE PHOTOLYSIS OF OZONE BETWEEN 287 AND 331 NM

The kinetic energies of the O-2(a (1) Delta(g)) fragment of the photol ysis of ozone at 14 wavelengths between 287.57 and 331.52 nm have been measured by time-of-flight spectroscopy. At wavelengths up to 308 nm, the behaviour is that expected from spin-allowed prompt dissociation of the excited molecule following absorption in a predominantly parall el transition. Between 308 and 318 nm, wavelengths which span the ther modynamic threshold for formation of excited singlet products at 310 n m, the spin-allowed dissociation of vibrationally excited ozone is obs erved. Photolysis at longer wavelengths produces fragments with higher kinetic energies, consistent with the formation of O-2(a (1) Delta(g) ) together with ground state O(P-3) atoms in a spin-forbidden process.