Simple Configuration-Interaction Wave Functions. I. Two-Electron Ions: A Numerical Study

Abstract

The ground state energies of the two-electron ions from H— to Ne8+ are calculated for the simple wave function (1s1s′)+λ(2p)2 with optimized orbital exponents. The use of the difference between the calculated energy and the experimental energy as a function of the atomic number for accurate extrapolation is explored. The expectation values of the operators rn(n≥—2), δ(3)(r1), and δ(3)(r12) are compared with those obtained from more accurate wave functions.