Angle-resolved two-dimensional mapping of electron emission following Cl2pexcitations in the HCl molecule

Angle-resolved Auger and valence photoelectron spectra of HCl were measured over a 14-eV-wide photon-energy range across the Cl $2p$ ionization thresholds. Auger decay spectra of dissociative core-excited states were observed to change with photon energy, reflecting a change in the rate of dissociation. Auger electron spectra at the first Rydberg states were analyzed and the evolution of the resonant Auger to the normal Auger decay distorted by postcollision interaction was examined. Valence photoionization channels were shown to resonate strongly at the photon energies of the core-to-Rydberg excitations. Angular distributions of the photo- and Auger electron lines were derived; strong fluctuations of the β values of the 2π photoline were observed at some Rydberg resonances. Anisotropy of the Auger decay at the ${\sigma }^{*}$ and Rydberg excitations was found to be different, with the latter showing uniformly negative β values.