Atomic and Molecular Calculations with the Pseudopotential Method. VIII Two-Valence-Electron Photoionization Cross Sections

Abstract

A two‐electron pseudopotential method is used to evaluate wavefunctions for the two‐valence‐electron systems: Li−, Be, B+, C+2, Mg, Al+, and Si+2 in the ns 2 1 S ground state and the nsεp 1 P continuum states. For the ground state and the continuum states of all the systems treated a Hartree–Fock wavefunction is used. In addition, for the ground states of the Be isoelectronic sequence a Hylleraas‐type correlated wavefunction for the two‐valence electrons with the following number of variational parameters is used: Li− 6 and 15 parameters; Be 6 and 20 parameters; and B+ and C+2 6 parameters. Using these wavefunctions the photoionization cross section for the ns 2 −nsεp transition is evaluated in both the dipole length and the dipole velocity forms for all systems. Previous calculated values, mostly for Be, are also discussed.