Inner-shell and outer-shell excitation of HCl, HBr and Br₂by electron impact with high resolution

Abstract

Electron impact excitation has been used to observe inner-shell and outer-shell excitation in HCl, HBr and Br2. Inner-shell energy-loss spectra have been obtained corresponding to excitation of a 2p electron in HCl and a 3d electron in HBr and Br2, at an incident energy of 1500 eV and with a resolution of typically 75 meV. The spectra are characterised by broad continua corresponding to excitation to unbound valence orbitals, and higher energy discrete structure corresponding to excitation into Rydberg orbitals. Assignments of these structures have been made and the binding energies of the inner-shell electrons have been deduced. Outer-shell, energy-loss spectra have been obtained in HBr and HCl under similar conditions.