Resonance asymmetry and external field effects in the photorecombination of Ti4+

We report on multiconfiguration Breit-Pauli calculations for the photorecombination of Ti4+ ions. Through a detailed comparison with the Test Storage Ring measurements of Schippers , we quantify the interference effects for the broad, asymmetric, near-threshold, highly correlated 3p(5)3d(2)(F-2) resonances. We also discuss the enhanced field ionization effects on recombined 3p(6)nl Rydberg states. This is due to the perturbation of the below-threshold tails of two of the broad 3p(5)3d(2)(F-2) resonances, giving rise to a "forced autoionization" phenomenon, increasing the field ionization effects. By accounting for interference for the lowest n=3,4 resonances, and field effects as n ->infinity, excellent agreement between our computed results and the experimental photorecombination spectrum is obtained.