Photoionization of $Sc^{+2}$

Photoionization cross section calculations are performed on the ground ($[Ne]3s^23p^63d{ }^2D_{3/2}^e )$ and the first two excited ($[Ne]3s^23p^63d{ }^2D_{5/2}^e $ and $[Ne]3s^23p^64s \quad { }^2S_{1/2}^e )$ states of $Sc^{+2}$ for photon energies from threshold to 68.0 eV. The discrete $Sc^{+3}$ orbitals are generated using the computer program AUTOSTRUCTURE; 24 configurations are included in the configuration-interaction (CI) calculation for $Sc^{+3}$. In addition to the non-relativistic (LS-coupling) R-matrix method, we have used the relativistic (Breit-Pauli) R-matrix method to carry out the calculations to focus on relativistic effects. The results are compared with previous theoretical results and existing experimental data, and rather good agreement with experimental data is obtained. The most prominent ($3p\to 3d)$ giant resonances are analyzed and identified, and our calculated positions and widths are compared with experimental results. This work is supported by US DOE and NASA.