UV Photodissociation Dynamics of C6H11Br by Velocity Map Ion Imaging

Abstract

The Photodissociation dynamics of C6H11Br was investigated near 234 nm. A two-dimensional photofragment ion-velocity imaging technique coupled with a (2+1) resonance-enhanced multiphoton (REMPI) ionization scheme was utilized to obtain the angular and translational energy distributions of the nascent Br(P-2(3/2)) and Br * (P-2(1/2)) atoms. The relative quantum yields were obtained from (2+1) resonance-enhanced multiphoton ionization (REMPI) of the photofragment Br*(P-2(1/2)) and Br(P-2(3/2)). It was suggested that Br* came from the direct dissociation of S-1 state mostly, while Br atom was produced by non-adiabatic transition between the S-2 and T-3 states. Consequently, the higher internal energy distribution and the broader translational energy distribution of Br channel than those of Br * formation channel can be explained well. The results indicated that a large fraction of the available energy translated into the internal energy of the fragments, which can be explained using the soft impulsive model. However, comparing with other long-chain bromoalkane, more available energy was translated into the kinetic energy. The relationship between the energy partition and the cyclohexyl radical structure were analyzed.