Atomic Autoionization Following Very Fast Dissociation of Core-Excited HBr

Abstract

Photoelectron spectroscopy excited by monochromatic synchrotron radiation (68-80 eV range) is used to study the Br $3d$ excitation in HBr. The transition to an antibonding orbital is shown to produce a resonant state whose repulsive nature has been observed directly. A two-step relaxation process involving a fast neutral dissociation followed by the autoionization of the excited fragment has been shown for the first time.