Refinement in the analysis of molecular Auger electron spectra: The2p−1→3pπ−2spectra of HCl and DCl

Abstract

High-resolution Cl ${2p}^{\ensuremath{-}1}$ photoelectron (PES) and Cl ${2p}^{\ensuremath{-}1}\ensuremath{\rightarrow}3p{\ensuremath{\pi}}^{\ensuremath{-}2}$ normal Auger electron spectra (AES) have been measured using different photon energies. The PES and AES have been fitted simultaneously taking vibrational and electronic lifetime-interference terms into account. Detailed results are presented for the Cl ${2p}^{\ensuremath{-}1}\ensuremath{\rightarrow}3p{\ensuremath{\pi}}^{\ensuremath{-}2}$ normal Auger transitions. The equilibrium distances, vibrational energies, and anharmonicities for the ${}^{1}{\ensuremath{\Sigma}}^{+},$ ${}^{1}\ensuremath{\Delta}$, and ${}^{3}{\ensuremath{\Sigma}}^{\ensuremath{-}}$ final states are derived from the intensity distribution of the vibrational substates. The relative intensities for the different Cl ${2p}^{\ensuremath{-}1}\ensuremath{\rightarrow}3p{\ensuremath{\pi}}^{\ensuremath{-}2}$ normal Auger transitions are also given. In addition to the Cl ${2p}^{\ensuremath{-}1}\ensuremath{\rightarrow}3p{\ensuremath{\pi}}^{\ensuremath{-}2}$ transitions, some fine structures are observed that show a photon energy dependence. These structures are assigned to decays of doubly excited or shake-up/off states.