Photoionization of the scandium atom. I. General features

In this paper we present the results of eigenchannel R-matrix calculations of the photoionization cross section of Sc from the 3d4${\mathit{s}}^2$ ${}_{}{}^2{}_{}{}^{}$ ${\mathit{D}}_{3/2,5/2}$ ground electronic state. The calculations were performed in LS coupling using configuration interaction for the target states as well as for the full atomic wave function. The spin-orbit interaction was incorporated through a recoupling frame transformation. We focus on the gross dynamics of the atom that need to be described accurately to obtain good agreement with experiment.