Photodissociation dynamcis of ClO radicals in the range (237≤λ≤270) nm and at 205 nm and the velocity distribution of O(1D) atoms

Isotopically selected photofragmentation of thermal ClO radicals was studied in the continuous and structured region of the A 2Π ← X 2Π transition in the wavelength range 237<λ<270 nm employing resonance enhanced multiphoton ionisation (REMPI) detection schemes. Photoexcitation of ClO generated Cl(2P3/2, 1/2) and O(1D) atoms with a quantum yield of unity. The translational energy of O(1D) was determined and quantified as a function of the wavelength of the incident radiation. Some experiments on the kinetic energy deposited in Cl(2P3/2, 1/2) are also reported. From the decrease of the O(1D) REMPI signal intensity approaching the transition from continuous to structured absorption, the cut-off excitation wavelength for O(1D) in thermal ClO radicals was evaluated to be 263.4±0.2 nm. In the structured region of the spectrum oxygen atoms are formed in the triplet ground state.