Effects of relativity on RTEX in collisions of U q+ with light targets

Abstract

We have calculated the resonant transfer and excitation cross sections in collisions of U q+ ( q = 82, 89 and 90) ions with H 2, He and C in impulse approximation using the multiconfiguration Dirac-Fock method. The calculations were carried out in intermediate coupling with configuration interaction. The quantum electrodynamic and finite nuclear size corrections were included in the calculations of transition energies. The Auger rates were calculated including the contributions from Coulomb as well as the transverse Breit interactions. For U 89+ and U 90+, effects of relativity not only shift the peak positions but also change the peak structure. The total dielectronic recombination strength has been found to increase by 50% due to the effects of relativity. The present theoretical RTEX cross sections for U 90+ in hydrogen agree well with experiment. For U 82+, Breit interaction has been found to have little effect on the RTEX cross sections involving L-shell excitation. However, the spin-orbit interaction can still make a significant change in the peak structure.