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.