R-matrix electron-impact excitation data for the Li-like iso-electronic sequence including Auger and radiation damping

Abstract

We present results for the electron-impact excitation of all Li-like ions from Be + to Kr 33+ which we obtained using the radiation-and Auger-damped intermediate-coupling frame transformation R-matrix approach. We have included both valence-and core-electron excitations up to the 1s 2 5l and 1s2l4l levels, respectively. A detailed comparison of the target structure and collision data has been made for four specific ions (O 5+ , Ar 15+ , Fe 23+ and Kr 33+ ) spanning the sequence so as to assess the accuracy for the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2 × 10 2 (z + 1) 2 K to 2 × 10 6 (z + 1) 2 K (where z is the residual charge of the ions, i.e. Z − 3). Detailed comparisons for the Υs are made with the results of previous calculations for several ions which span the sequence. The radiation and Auger damping effects were explored for core-excitations along the iso-electronic sequence. Furthermore, we examined the iso-electronic trends of effective collision strengths as a function of temperature.

CHIANTI – An atomic database for emission lines. Version 8

“…Na ix, P xiii, Cl xv, K xvii, Mn xxiii, and Co xxv For these ions we have retained the original 204 levels and the original energies, A-values and all the effective collision strengths as calculated by Liang & Badnell (2011). To reduce the size of the data files containing the radiative rates, we have retained for all the new datasets only transitions with an A-value greater than 10 −5 the largest A-value (for each level).…”

“…We have included only the collision strengths of Liang & Badnell (2011) from the 2s and 2p levels. The data have been spline-fitted over a reduced number of temperatures.…”

“…Liang & Badnell (2011) have performed, within the UK APAP network, scattering calculations for electron-impact excitation of all Li-like ions from Be + to Kr 33+ using the radiationand Auger-damped intermediate-coupling frame transformation R-matrix approach. The target included 204 close-coupling (CC) levels, with valence (up to n = 5), and core-electron excitations (up to n = 4).…”

“…We have calculated the autoionization rates using AUTOSTRUCTURE (version 24.24) and the same set of scaling parameters used by Liang & Badnell (2011) for consistency. For Na ix, experimental energies have been reassessed on the basis of the wavelength measurements as reported in Kelly (1987).…”

Responsivity calibration of the extreme ultraviolet spectrometer in the range of 175-435 Å

“…This MBPT approach has been proved to be significant improvement in accuracy compared with the relativistic configuration interaction (RCI) method in the FAC code. 27,28 The close-coupling R-matrix approach 29 were utilized to provide the collision strength of electron impact excitation. In order to include the cascade contribution on the excited level population, the collision excitation from the ground or lower n states to higher n states which were not offered by R-matrix data were solved via the relativistic distorted wave (DW) method in FAC.…”