NOTE ON THE VARIATION STEP IN THE ITERATION-VARIATION APPROACH - ILLUSTRATION ON THE HYDROGEN-ATOM

An analysis of the analytical properties of the first iterate of the i teration-variation approach applied to small Gaussian expansions is re ported in the case of the hydrogen atom. The first iterates embody imp ortant qualitative improvements such as a cusp near the origin and bet ter asymptotic decay at large values of r. Actual values, of the prope rties depend on the quality of the initial functions in such a way tha t for very small Gaussian expansions the variation step is necessary. (C) 1995 John Wiley and Sons, Inc.