Photodissociation dynamics of CF3Br at 234 nm:: An implication of symmetry reduction during photodissociation

The photodissociation dynamics of CF3Br in the A-band has been investigated utilizing a two-dimensional photofragment ion-imaging technique coupled with a state-selective resonance-enhanced multiphoton ionization scheme. The total translational energy distributions for the Br(P-2(3/2)) and Br*(P-2(1/2)) channels are well characterized by Gaussian functions with average translational energies of 183 and 151 kJ/mol, respectively. The recoil anisotropies were measured to be beta =0.66 for Br and 1.83 for Br*. It was found that Br* production is preferred, with a relative quantum yield of 0.80. The reduction in the recoil anisotropy for Br results from nonadiabatic coupling between the (1)Q(1) and (3)Q(0) states. The fraction of molecules that dissociate via a distorted pathway induced by symmetry reduction from C-3v to C-s is estimated to be 0.11. (C) 2001 American Institute of Physics.