Experimental aspects and Z-dependent systematics in one- and two-electron ions and single vacancy systems

Abstract

Some predominantly experimental considerations concerning both few electron highly charged ion spectra and inner-shell vacancy spectra are discussed in relation to the currently available theoretical approaches. For the cases of H-like and He-like spectra theoretical machinery appears to be well in hand particularly in comparison to the relatively sparse experimental database which is also of limited accuracy in most cases. Owing particularly to some impressive recent theoretical progress on the problem of nearly neutral ions containing inner-shell vacancies, the traditional x-ray data suitably filtered and strengthened by modern measurements, appear to offer some quite useful insights in spite of their formidable complexity. With the advent of new storage ring facilities and advanced technology ion sources as well as a new effort on transuranic x-ray spectra, one can reasonably foresee an upcoming period of fruitful activity.