Recent Developments in Accelerator Based Atomic Physics

Much progress toward a detailed understanding of atomic collision phenomena and atomic structure has recently been made with the aid of accelerated ion beams. Beam foil Lamb shift measurements and the possible observation of spontaneously created positrons from quasi-superheavy atoms give promise for critical tests of QED. The mechanisms of innershell ionization and charge transfer in ion atom collisions have been intensively investigated and the results have brought together the various approaches - Coulomb excitation and MO treatments for these processes. That violent collisions at high energies can cause multiple ionization of the target atom has been known for some time. However, only recently have theoretical treatments been able to predict, e.g., the degree of L shell ionization accompanying K shell ionization. The highly charged ions formed in these collisions have themselves come under intensive investigation and are used for the study of the structure and collision physics of multiply charged species. Electron-Ion collision studies have also been started and initial results on dielectronic recombination are reported.