Photoionization of Heavy Atomic Ions

Photoionization cross sections of heavy atomic elements, in low stages of ionization, are currently of interest both experimentally and in astrophysics. The data from such processes have many applications in planetary nebulae, where they are of use in identifying weak emission lines of $n$-capture elements. Furthermore, photoionization experiments on heavy atomic ions, at the Advanced Light Source (ALS) in Berkeley, has highlighted the need to have high quality calculations in order to fully interpret experimental data. A recently developed relativistic R-matrix code (DARC), for parallel architectures, has been modified now to include photoionization processes. We have performed calculations for photoionization cross sections, on a number of different atomic ion species (Se, Kr, Ar and Xe) in their low stages of ionization, using both the Breit-Pauli and the relativistic Dirac-R-matrix method. Where possible, we compare our theoretical results with ongoing experiments being performed at the ALS. Such comparisons indicate suitable agreement and serve as the ultimate benchmark for our work. Further details will be presented at the meeting.