PROJECTILE EXCITATION AND IONIZATION IN RELATIVISTIC ION-ATOM COLLISIONS

K-shell ionization and excitation is studied for high-Z one-and two-el ectron ions in relativistic encounters with low-Z targets. For ionizat ion, the data obtained for solid and gaseous targets are compared in d etail with the predictions of first order perturbation theory. On the basis of the most recent experimental results, the systematic deviatio n from first order perturbation theory as observed recently for high-Z ions cannot be confirmed. Moreover, special emphasis is given to a de dicated experiment where projectile excitation has been studied in enc ounters of heavy one-and two-electron bismuth ions (Z = 83) with light solid targets. The measurement of the characteristic ground-state tra nsitions in coincidence with the primary charge state allowed us to st udy the formation of excited projectile states via direct Coulomb exci tation. In particular, due to the large fine-structure splitting, the excitation cross-sections for the various L-shell sublevels in H- and He-like bismuth could be determined separately, The results are compar ed with detailed relativistic calculations showing that for high-Z pro jectiles the magnetic interaction is of considerable importance at the considered collision energies.