SELF-CONSISTENT APPROXIMATE SOLUTION OF THE 2ND-ORDER CONTRACTED SCHRODINGER-EQUATION

The general theoretical background for solving approximately the contracted Schrodinger equation (CSchE) in a self-consistent (SC) way has recently been proposed [F. Colmenero and C. Valdemoro, Phys. Rev. A 47, 979 (1993)]. Here, a spin-free procedure is developed and the convergence of the SC iterative process is analyzed using as test cases the beryllium atom and four isoelectronic ions in their ground states. Damping and extrapolation procedures are employed to improve and accelerate the convergence. The results obtained are in very close agreement with those obtained by means of the full configuration-interaction (FCI) method. (C) 1994 John Wiley & Sons, Inc.