Photoionization and Electron-Ion Recombination of Ar~XVI and Ar~XVII

Results on photoionization and electron-ion recombination of Ar~XVII and Ar~XVII obtained from unified method will be reported. The method, based on relativistic Breit-Pauli R-matrix method and close-coupling approximation, (i) subsumes both the radiative and dielectronic recombination and (ii) provides self-consistent sets of photoionization and recombination cross sections, $\sigma_{PI}$ and $\sigma_{RC}$. Important features for level-specific $\sigma_{PI}$ and recombination rate coefficients ($\alpha_R$), such as for diagnostic w, x, y, z X-ray lines of Ar~XVII in the ultraviolet region of astrophysical spectra will be illustrated. Monochromatic decay dominates the low energy photoionization and low temperature recombination rates. However, high energy resonances in $\sigma_{PI}$ introduce a DR bump at high temperature recombination. While the 1s-2p core excitations enhance the background of $\sigma_{PI}(nSLJ)$ at n=2 thresholds. the resonances become much weaker beyond them. The extensive sets of results correspond to fine structure levels with $n \leq 10$ and $0 \leq l \leq 9$. They include 98 levels of Ar~XVI of total angular momenta 1/2 $\leq J \leq$ 17/2 and 191 levels of Ar~XVII of $0 \leq J \leq 9$. The present $\alpha_R(T)$ with temperature show good agreement with ava