Radiative electron capture in relativistic ion atom collisions and the photoelectric effect in hydrogen like high Z systems

In recent years, radiative electron capture REC in high energy ion atom collisions from a low Z target into a bare or few electron high Z projectile up to U92 has been studied in great detail. This process, in which an electron is transferred from the target to the projectile with the simultaneous emission of a photon, plays an important role in spectroscopic studies of high Z few electron atoms. Being the inverse reaction of the atomic photoelectric effect, it also provides a means of investigating the latter in a high energy regime that is otherwise almost inaccessible. In the present article, the experimental techniques as well as the theoretical developments are reviewed, and a summary of results is given