Electron Impact Excitation of Al XIII: Collision Strengths and Rate Coefficients

Collision strengths for all transitions up to and including the n = 5 levels of Al XIII have been computed in the LS coupling scheme using the R -matrix code. All partial waves with angular momentum L ≤ 45 have been included, and resonances have been resolved in a fine energy grid in the threshold region. Collision strengths are tabulated at energies above thresholds in the range 162.30 ≤ E ≤ 220.0 Ry, and results for the 1s–2s and 1s–2p transitions are compared with those of previous authors. Additionally, effective collision strengths, obtained after integrating the collision strengths over a Maxwellian distribution of electron velocities, are tabulated over a wide temperature range of 4.40 ≤ log T e ≤ 6.40 K.