Avoided curve crossing between the A(1) and B-1 states in CF2Br2 photolysis at 234 and 265 nm

The photodissociation dynamics of CF2Br2 has been studied using a two-dimen sional photofragment ion image technique for the two excitation wavelengths 234 and 265 nm. At 234 nm,three dissociation channels, i.e., the radical C F2Br + Br(P-2(J))(J = (1)/(2), (3)/(2)), the three-body CF2 + 2Br (P-2(J)) (J = (1)/(2), (3)/(2)), and the molecular elimination channel CF2 + Br-2, w ere observed with quantum yields of 0.84, 0.15, and trace, respectively. Th e difference between beta (CF2Br + Br (P-2(3)/(2))) = 0.65 and beta (CF2Br + Br (P-2(1/2))) = 0.80 suggests that the excited A(1) and B-1 states are s trongly correlated by avoided curve crossing with a probability of 0.78. At 265 nm, the radical channel, the observed major primary dissociation chann el, shows several components due to the transition close to the curve:cross ing point. On the basis of observations at both wavelengths, we have propos ed a photodissociation dynamics model of CF2Br2 after A-band excitation.