Photofragment alignment from the photodissociation of HCl and HBr

Abstract

Slice imaging is used to measure the alignment of Br( 2 P 3/2) and Cl( 2 P 3/2) photofragments from the photodissociation of HBr and HCl, respectively, at 193 nm. In both cases the A 1Π 1 state is predominantly optically excited, which correlates to m J =±3/2 for the halogen atom photofragments. However, both the Br and Cl photofragments are measured to populate mostly m J =±1/2, showing that for both HBr and HCl nonadiabatic transitions transfer more population to the a 3Π 1 state (which correlates to m J =±1/2) during dissociation than remains in the A 1Π 1 state. The interference between these two pathways is also measured.