Photo recombination on highly charged few-electron uranium ions

The theory of photo recombination is reviewed and cross sections for radiative and dielectronic recombination and for interference between both processes are derived by an expansion of the T-matrix in low order. In order to demonstrate the interference effects, KLL-photo recombination cross sections are calculated for hydrogen-and helium-like uranium ions. The radiative recombination cross sections are obtained with a multipole expansion for the radiation field leading to an increase of the cross sections by a factor of 2 compared with calculations in the dipole approximation. The effect of interference is found to be strongest in hydrogen-like very heavy ions.