Angular distribution of positive photofragments following dissociative double ionization in the HBr molecule

Dissociative rates from the five doubly ionized states in the HBr molecule associated with the first two dissociation limits have been measured by recording the kinetic energy spectra of the H + signal using monochromatic as well as white synchrotron radiation. The direct double ionization of the 4p pi valence electrons is found to be only weakly affected by electron interactions. Photoabsorption in the region of the 3d excitation in Br is highly anisotropic, as reflected by the angular dependence of the photofragment distributions. Comparisons with results based on potential energy curves for HBr 2+ calculated employing multi-reference configuration interaction (MRD-CI) are presented and a good agreement between theory and experiment is found.