The Dynamics of Br Formation from the Primary and Secondary C-Br Bond Dissociation of Oxalyl Bromide near 265 and 234 nm

Abstract

The photodissociation dynamics of oxalyl bromide is investigated near 265 and 234 nm using the velocity map ion imaging technique coupled with a state selective [2+1] resonance-enhanced multiphoton ionization scheme. The translational energy distribution and P-2(J), J = 3/2, 1/2 parameters of the Br atom formation process are extracted from two-dimensional ion images. The trimodal energy distribution of Br(P-2(3/2)) atoms is attributed to the primary C-Br bond fission as well as the secondary dissociation of bromine-containing C2O2Br radicals produced from the primary Br and Br* pathways. The conclusions are confirmed by the recoil anisotropy and the distribution width corresponding to the individual components. The branching ratio Br(P-2(3/2))/Br(P-2(1/2)) confirms the excitation energy dependence.