Doubly-excited intrashell states of a two-electron atom: exact wavefunctions in the large-n limit

Abstract

Lower S and P states of the n2-manifold of a two-electron atom are studied. The analytical wavefunctions of these states, being exact in the large-n limit, are obtained using diagonalization of the two-electron 'dipole' operator. These wavefunctions (As-n functions) are shown to be eigenvectors of the operator r-112 in the large-n limit. The As-n functions are very good approximations of exact wavefunctions even at small and moderate n (overlap integral)0.999 at n>or=4). The use of the As-n functions allows the specific features of the electron distribution in l to be elucidated.