The cross section for K+ photoionisation has been calculated at the relativistic random-phase approximation level and found to be in excellent agreement with a recent experimental investigation.

The photoionization cross section for ${\mathrm{Al}}^{+}$ has been calculated within the framework of the relativistic random-phase approximation including all 1s, 2s, 2p, and 3s channels. Except for the first few eV above threshold, it is found that the simple Hartree-Slater central-field result agrees with this cross section of 10% or better, indicating that multichannel effects drop off rapidly with stage of ionization.

The angular distribution for Ar 2p photoionization has been measured from just above threshold to 400 eV photon energy, and calculated in the same energy range using the relativistic random-phase approximation. The present experimental and theoretical results are in good agreement, but disagree somewhat with earlier Hartree-Fock (HF) calculations. The HF values are found to be significantly higher in the near-threshold region. Possible reasons for this discrepancy are discussed with relevance to the general understanding of inner-shell photoionization phenomena.