Time-of-flight measurements of the kinetic energies of the O2(a 1Δg) fragment from the photolysis of ozone between 287 and 331 nm

The kinetic energies of the O2(a 1Δg) fragment of the photolysis 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 parallel transition. Between 308 and 318 nm, wavelengths which span the thermodynamic threshold for formation of excited singlet products at 310 nm, the spin-allowed dissociation of vibrationally excited ozone is observed. Photolysis at longer wavelengths produces fragments with higher kinetic energies, consistent with the formation of O2(a 1Δg) together with ground state O(3P) atoms in a spin-forbidden process.