EXCHANGE AND FINE-STRUCTURE EFFECTS IN AUTOIONIZATION OF LARGE-ANGULAR-MOMENTUM DOUBLY-EXCITED RYDBERG STATES

Autoionization probabilities of doubly excited atoms with one electron in a large-I Rydberg state are investigated through first-order pertu rbation theory in a single-configuration approach. In the framework of the jk-coupling scheme, the formalism takes into account multipoles h igher than dipoles in the electronic interaction and exchange effects. Exchange effects are computed using the Froese method for Slater inte grals and are demonstrated to be significant as long as l < 5. The ess ential importance of fine-structure transitions when the outer electro n is in a large-l state is emphasized. Comparison with available exper imental data shows that Slater integrals are reliably computed and tha t.fair agreement is generally obtained for g states, while even strong ly autoionizing f states are at least qualitatively represented. Corre lation effects may explain some remaining disagreement with the measur ed autoionization widths.