Collision-strength dependence of solar emission lines of Si(X) and S(XII)

We have calculated the normalized populations of 15 levels in Si(X) and S(XII) ions in an optically thin medium, under steady-state condition, by using (i) constant collision strengths computed at the incident electron energy kT_e and (ii) incident electron-energy-dependent collision strengths. To calculate intensity ratios for solar emission lines, one may use constant collision strengths at the electron energy E'.