Convergent close-coupling calculations of atomic double ionization

Convergent close-coupling (CCC) theory, originally developed to describe electron-atom collisions [1], was applied, with a great success, to atomic double photoionization (DPI). DPI from He and its isoelectronic sequence had been studied extensively and prediction of the theory in most cases had been confirmed experimentally [2]. Here we present latest applications of the CCC method to DPI which go beyond simple helium-like targets. The frozen-core approximation is used to describe DPI from the valence shell of Be and heavier alkaline-earth atoms as well as the outermost $np^6$ subshell of noble gases. A ``hybrid'' model combining a target-specific ground state and a He-like final state is employed to describe DPI from subvalent $2s^2$ shell of Ar and the H$_2$ molecule. Extension of the theory to describe DPI in strong laser fields is discussed. \begin{thebibliography}{1} \bibitem{BS95b} I. Bray and A.~T. Stelbovics, Adv.~Atom.~Mol.~Phys. {\bf 35}, 209 (1995). \bibitem{KB98d} A.~S. Kheifets and I. Bray, Phys.~Rev.~A {\bf 58}, 4501 (1998). \end{thebibliography}