We present measurements of the absolute photoionization cross section of the aluminumlike ${\mathrm{Si}}^{+}$ ion over the 94–137 eV photon energy range. The measurements were performed using the merged-beam setup on the PLEIADES beamline at the SOLEIL synchrotron radiation facility. Signals produced in the ${\mathrm{Si}}^{2+}$ and ${\mathrm{Si}}^{3+}$ photoionization channels of the $2p$ subshell of the ${\mathrm{Si}}^{+}$ ion from both the $1s^{2}2s^{2}2p^{6}3s^{2}3p{}^2{P}_{1/2,3/2}$ ground levels and the $1s^{2}2s^{2}2p^{6}3s3p^2{}^{4}P$ metastable levels were observed. Absolute cross sections were determined. Calculations of the $2p$ inner-shell photoionization cross sections were carried out using the multiconfiguration Dirac-Fock and Dirac-Coulomb R-matrix theoretical approaches and are compared with experiment.

• Received 10 September 2014

DOI:https://doi.org/10.1103/PhysRevA.90.063409