Electron impact excitation of Kr XXVIII

Collision strengths (Ω) are calculated for all 6328 transitions among the lowest 113 levels belonging to the 2 s 2 2 p 5 , 2 s 2 p 6 , 2 s 2 2 p 4 3 ℓ , 2 s 2 p 5 3 ℓ , and 2 p 6 3 ℓ configurations of fluorine-like krypton, Kr XXVIII, using the Dirac Atomic R-matrix Code. All partial waves with angular momentum J ⩽ 40 are included, sufficient for the convergence of Ω for forbidden transitions. For allowed transitions a top-up is employed to obtain converged values of Ω up to an energy of 400 Ryd. Resonances in the thresholds region are resolved on a narrow energy mesh, and results for effective collision strengths (ϒ) are obtained after averaging the values of Ω over a Maxwellian distribution of electron velocities. Values of ϒ are reported over a wide temperature range below 10 7.1 K , and the accuracy of the results is assessed. In addition, effective collision strengths are listed for the temperature range 7.0 ⩽ log T e ( K ) ⩽ 9.0 , obtained from non-resonant collision strengths generated with the FAC code.