ON THE ACCURACY OF THE COULOMB APPROXIMATION AND A MODEL-POTENTIAL METHOD FOR ATOMIC TRANSITION-PROBABILITIES IN ALKALI-LIKE SYSTEMS

A numerical Coulomb approximation and a model-potential method are used to estimate oscillator strengths for dipole-allowed transitions in Na, Mg+, K and Ca+. Core-polarisation corrections to the dipole operator are included. Comparison of excited-state lifetimes with accurate experimental measurements demonstrates the high accuracy that may be achieved with relatively simple computational procedures. A novel long-range form of the electric dipole operator is introduced.