Photoionization of ions of astrophysical interest: Theoretical survey

The need for accurate data for the interpretation of astrophysical plasmas continues apace: transition probabilities, electron scattering rates and photo-ionization cross sections/radiative rates. Planetary nebulae. infra-red galaxies, extragalactic regions are some of the examples where data are required. Missions such as the Infrared Space Observatory, Chandra and Newton are all providing observational data of the highest quality. In this paper. we look at where theoretical photo-ionization cross section data may be found. We consider first the large scale calculations and attempt to provide some idea of the accuracy of these calculations. We focus particularly on the data produced by the R-matrix method. We then turn to some specific elements considered by the Belfast group. In particular we will discuss the 1s-shell excitation/ejection in the photoionization of the 1s(2) 2s(2), 2p P-2(O) ground states of N III and O IV.