Target effects on the linear polarization of photons emitted in radiative electron capture by heavy ions

Radiative electron capture by highly-charged, heavy ions is re-investigated within the framework of the first-order perturbation theory and impulse approximation. In this study, we focus especially on the polarization properties of the emitted radiation and on the effects which arise from the binding of the target electrons. In order to explore such effects, detailed calculations have been carried out for relativistic collisions of bare uranium U92+ projectiles with neutral low- and medium-Z atoms. From these calculations, it is shown that the linear polarization of K-REC (L-REC) photons [photons originating from radiative electron capture into the K shell (L shell)] can be very sensitive to the momentum distribution of bound electrons if the capture occurs selective for the different shells of the target. The most pronounced effect can be observed for collision studies as performed with well-defined impact parameters or upon suppression of the capture from the outer target shells.