The role of the Δn = 2 core excitations in the dielectronic recombination of M-shell Fe ions: the Na, Mg and Al isoelectronic sequences

The important role played by dielectronic recombination (DR) of M-shell Fe ions in the observed absorption X-ray spectra of Seyfert galaxies [1,2] have encouraged a thorough investigation of the related plasma DR rate coefficients in support of astrophysical observations. So far, theoretical modelling of such processes has accounted for the sole contributions due to Δn = 0,1 excitation channels (see, for instance, [1]). However, it was pointed out that at reasonably high temperatures even the neglected Δn = 2 channels may remarkably contribute to the total temperature-dependent DR rates [3]. This has spurred us to investigating the contribution of the Δn = 2 excitation channels for the 2 → 4 and 3 → 5 resonances to the plasma rate coefficients of initially Na-like and Mg-like Fe ions in the 104 – 109 K temperature range, by means of the Multi-Configurational Dirac-Hartree- Fock method. As a result, the contribution to the total plasma DR rates due to this excitation channel was found to be remarkable in the collisionally-ionized plasma region.

[1] Z. Altun, A. Yumak, N.R. Badnell, S.D, Loch, and M.S. Pindzola, A&A 447, 1165-1174 (2006).

[2] Z. Altun, A. Yumak, I. Yavuz, N.R. Badnell, S.D. Loch, and M.S. Pindzola, A&A 474, 1051-1059 (2007).

[3] S. Schippers, M. Lestinsky, A. Muller, D.W. Savin, E.W. Schmidt and A. Wolf, IRAMP 1, 2 (2010), 109-121.

https://gsi-fair.zoom.us/j/63856816325
Meeting-ID: 638 5681 6325
Passcode: AP_Seminar
dial by phone
+496938079884,,63856816325#,,,,*8527227260# Deutschland
+496950500951,,63856816325#,,,,*8527227260# Deutschland
AP_Seminar_