Photodissociation of C3H5Br and C4H7Br at 234 nm

Abstract

The photodissociation dynamics of cyclopropyl bromide (C3H5Br) and cyclobutyl bromide (C4H7Br) at 234 nm was investigated. A two-dimensional photofragment ion-imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization scheme was utilized to obtain speed and angular distributions of the nascent Br(P-2(3/2)) and Br-*(P-2(1/2)) atoms. The recoil anisotropies for the Br and Br-* channels were measured to be beta Br = 0.92 +/- 0.03 and beta(Br*) = 1.52 +/- 0.04 for C3H5Br and beta(Br) = 1.10 +/- 0.03 and beta(Br*) = 1.49 +/- 0.05 for C4H7Br. The relative quantum yield for Br was found to be Phi(Br) = 0.13 +/- 0.03 and for C3H5Br and C4H7Br, respectively. The soft radical limit of the impulsive model adequately modeled the related energy partitioning. The nonadiabatic transition probability from the 3A' and 4A' potential energy surfaces was estimated and discussed.