R-matrix inner-shell electron-impact excitation of Fe${}^{15+}$ including Auger-plus-radiation damping

Abstract

We present results for the inner-shell electron-impact excitation of Fe${}^{15+}$ using the intermediate-coupling frame transformation {\it R}-matrix approach in which Auger-plus-radiation damping has been included. The target and close-coupling expansions are both taken to be the 134 levels belonging to the configurations $2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3l$, $2{\mathrm{s}}^{2}2{\mathrm{p}}^{5}3s3l$, $2{\mathrm{s}}^{2}2{\mathrm{p}}^{5}3{\mathrm{p}}^2$ and $2{\mathrm{s}}^{2}2{\mathrm{p}}^{5}3p3d$. The comparison of Maxwell-averaged effective collision strengths with and without damping shows that the damping reduction is about 30-40% for many transitions at low temperatures, but up to 80% for a few transitions. As a consequence, the results of previous Dirac $R$-matrix calculations (Aggarwal and Keenan, 2008) overestimate the effective collision strengths due to their omission of Auger-plus-radiation damping.

21 pages, 7 figures, 4 tables. accepted by J. Phys. B

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• Collisional Ionization Equilibrium for Optically Thin Plasmas. I. Updated Recombination Rate Coefficients for Bare though Sodium-like Ions