We present a direct method for calculation of radiative electron capture (REC) X-ray emission in relativistic ion-atom collisions. Results obtained within the distorted-wave impulse approximation (DWIA) are compared with recent experimental data for the collisions of heavy ions with light atoms. Simple closed analytic formulae are derived for small αZ describing the polarization and the angular distribution of radiation.
Good agreement with recent experiments is found for photoemission rates and angular distributions. Our results for helium and beryllium targets indicate that the photon spectrum is rather insensitive to target structure, but strongly dependent on multiple-scattering corrections, and this contradicts other recent theoretical predictions. In asymmetric collisions our results are in broad agreement with experiment and relativistic impulse approximation (RIA) calculations. Through detailed analysis of magnetic transitions in terms of the electron and photon polarization correlation parameters, important new features are introduced and discussed.