New Investigation of the 1<i>Se</i>Autoionizing States of He and H−

Abstract

The present investigation should provide some insight into the convergence properties of some particular upper roots of the full Hamiltonian. In this connection detailed calculations using the scaling-variation orthogonalization procedure with different subsets of the basis up to order 54 have been carried through both for He and H−. Subsets including basic functions up to g—g are used, and a complete mapping of the ten lowest roots of the energy matrix by a continuous variation of the scale factor has been carried out within a definite range. The investigation clearly demonstrates the stabilizing ability of particular upper roots throughout the extension of the basis if the orthogonalization is properly achieved. These roots in the second-step solution may be associated with certain autoionizing states (quasi doubly excited, discrete states). The eigenvalues, obtained by optimizing the scale factor for these roots, are compared with those obtained for resonance positions in He+ and H elastic-scattering calculations by using other approximate methods, and by experiments.