Spectroscopic study of Fe IV and photoionization of Fe III ions under dense plasma

The influence of plasma screening on the excitation energies of V-like Fe ions embedded in the plasma environment has been analyzed. For this purpose, the Flexible Atomic Code (FAC) incorporates the analytical ion sphere plasma screening potential to study the plasma environment effect in the atomic structure of V-like Fe ions and photoionization of Cr-like Fe ion. We have compared our calculated transition wavelengths for 12 strong lines of Fe IV ion with 12 strong undetected lines of hot DA white dwarf G191-B2B [1]. The effect of plasma on photoionization cross-section and ionization potential depression for ground state of (Fe III) ion are studied at electron densities from 1019cm-3 to 1021cm-3. The present results should be helpful in the diagnostics of laboratory and modeling of astrophysical plasmas.