The excitation of inner shells in slow atomic collisions

The development of the theory of inner-shell excitation in slow ion-atom collisions over the past decade is described. This theory recognizes that electrons in inner shells behave largely independently of other electrons and generalizes the coupled-state impact-parameter method used successfully for ion-atom collisions involving a single electron. The method utilizes one-electron molecular orbitals obtained from solutions of the stationary molecular Shcrodinger equation and the generation of such orbitals for inner-shell electrons is described. The solution of the coupled equations for the excitation of K-shell electrons in collisions of first-row atoms is considered in detail, particularly the scaling properties. A discussion is given of the limitations of the independent-electron method and the role played by the outer-shell electrons.