Competition between atomic and molecular Auger decays: Study of the resonant Auger decay of HBr after the Br 3d--> sigma * transition.

High-resolution (width ∼0.12 eV) resonant Auger spectra of HBr and DBr after the Br 3d→σ * transition are reported. Besides the atomic decay of Br * (3d 9 4s 2 4p 6 ) produced by dissociation of HBr after the antibonding transition, the molecular decay of HBr * (3d 9 σ *1 ) is also observed in this high-resolution study. Competition between the atomic and molecular decay is influenced by varying the photon energy and by isotopic substitution