Study of the multicharged ion Ar6+ by a configuration-interaction Hartree-Fock method using a pseudopotential

An approach to studying excited states of atoms or ions with two optically active electrons outside an ionic closed-shell core is applied to the multicharged ion Ar6+. The interaction between the core and one valence electron is modelled by an accurate semi-empirical pseudopotential based on a new definition of the ionization potential of the ion Ar7+. Additional information about spectroscopic data of this ion is then obtained. For any given parity and total angular momentum, single-configuration Hartree-Fock calculations are performed to build a basis set of numerical two-electron wavefunctions for the ion Ar6+. Configuration-interaction calculations then provide the energy positions of the Ar6+ correlated states, and their compositions in terms of the single-configuration basis set. The estimated good accuracy of our calculations allows the identification of both photoemission lines and Anger decays, which are observed after charge-exchange collisions between Ar8+ or Ar7+ ions and atomic or molecular targets.