| Abstract: | The role of the continuum, so important in ground-state properties, is known to be less important and may even be negligible in the computation of polarizabilities and other higher negative moments of the oscillator strength distribution. This can be rationalized in terms of the solutions of the inhomogeneous equation generating the moments as an alternative to the dominating first term in an eigenfunction expansion. This leads in a natural form to the approximation F?0(1 + w(r)) for the perturbed wave function where 1 + w(r) represents a nonuniform scaling of the unperturbed function ?0. |
