Experimental and theoretical studies of the photoionization cross section of Fe{sup 4+}

We have measured the absolute photoionization cross section of the Fe{sup 4+} ion between 59 and 140 eV photon energy, including the region of the 3p{yields}3d excitations. To interpret the data we have performed calculations using a code developed for the determination of the spectral opacity of hot plasmas. We have also compared our measurements with the results of several R-matrix calculations. In short, both theoretical approaches describe qualitatively the results of the experiment in the 3p-3d excitation region.