PHOTODISSOCIATION DYNAMICS OF OCLO - O(P-3(J)) STATE AND ENERGY-DISTRIBUTIONS

The photodissociation dynamics of OClO in the near ultraviolet (UV) wa s investigated in a state specific and energy selective manner. At a d issociation wavelength of 308 nm, OClO((X) over tilde(2)B(1)) was exci ted to the OClO((A) over tilde(2)A(2)(18,0,0)) state, from which it de cays into ClO(X-2 Pi(3/2,1/2)) and O(P-3(2,1,0)). The nascent oxygen f ragments were detected spin selectively by resonant enhanced multiphot on ionization and time of flight measurements (REMPI-TOF). Based on th e measurements and the conservation of energy and linear momentum, the internal energy of the ClO partner fragment was obtained. On average, more than 60% of the available energy is transferred into internal ex citation of the ClO radical. Nearly the whole internal energy is vibra tional energy with vibrational levels populated up to the energetic li mit. Besides, the internal energy depends on the oxygen spin-orbit sta te because the fraction of highly excited ClO fragments increases with increasing total angular momentum J. The bimodal behavior of the frag ment energy distribution indicates two different dissociation pathways , in which one leads to ClO radicals excited up to upsilon = 10 and th e other one up to upsilon = 15. Furthermore, the decay is anisotropic, which was proved by polarization experiments. This is a hint for a sh ort decay time estimated to be in the order of a few hundred femtoseco nds. (C) 1997 American Institute of Physics.