Absolute oscillator strengths for the partial photoionization, ionic fragmentation and photoabsorption of HCl

Abstract

Abstract Absolute dipole oscillator strengths (cross sections) for the partial photoionization of HCl to the X2Π, A2Σ+ and B2Σ+ states of HCl+ have been measured in the photon energy range up to 40 eV using dipole (e,2e) spectroscopy. Results are in reasonable agreement with recent calculations by Faegri and Kelly for the ground and first excited ionic state. Binding energy spectra show that ionization from the 4σ orbital is split into a manifold of final ion states in accord with predictions of recent many-body calculations and also with measurements using binary (e,2e) spectroscopy. Dipole oscillator strengths for molecular and dissociative photoionization are also measured up to 40 eV using (e,e+ion) spectroscopy. The absolute oscillator strength for photoabsorption of HCl is reported up to 60 eV. The previously unreported appearance potential of H+ from HCl is measured to be 18±1 eV. The results from the dipole (e,2e) and (e,e+ion) measurements are combined to provide a quantitative estimate of the dipole breakdown pattern of HCl in the energy range up to 40 eV.