Photodissociation dynamics of Cl2O: Interpretation of electronic transitions

The photodissociation of Cl 2 O has been investigated for adjacent regions in the first and the second absorption bands, respectively, at dissociation wavelengths of 5.3 and 6.0 eV. Chlorine and oxygen atoms were state;electively detected by resonance-enhanced multiphoton ionization. Chlorine fragment kinetic energy and spatial distributions were determined from time-of-flight profile analysis. At 5.3 eV, kinetic energy distributions are broad and bimodal and differ significantly for the two spin-orbit states Cl*( 2 P 1 / 2 ) and Cl( 2 P 3 / 2 ). The decay is characterized by a positive anisotropy parameter of 0.7 ′ 0.2. Excitation proceeds via the transitions 10a 1 ← 7b 2 and 10a 1 ← 9a 1 . The data are in agreement with generating CIO(X) + Cl*( 2 P 1 / 2 ) as primary fragments. At 6.0 eV. kinetic energy distributions are narrow and structureless and are similar for the two spin-orbit states Cl*(2P 1 / 2 ) and Cl( 2 P 3 / 2 ). The decay is characterized by a small positive anisotropy parameter of 0.2 ′ 0.2. The main dissociation channel is the three-body decay into 2Cl + O. The decay mechanism is of an asynchronous concerted type. The data suggest the primary production of ClO(A) + Cl( 2 P J ). Excitation proceeds mainly via the transition 8b 2 ← 7b 2 . The results show the need for refined theoretical calculations.