Calculation of photon angular distribution and polarization for radiative recombination for highly charged helium-like ions

A systematic study is carried out on the angular distribution and polarization of photons emitted following radiative recombination of He-like ions by a non-relativistic dipole approximation. In order to incorporate the screening effect due to inner-shell electrons, a distorted wave approach is used. The dependence of the calculated angular distribution and polarization on the reduced-energy and nuclear charge are fitted by the corresponding empirical formulas, respectively.