(Effective) collision strengths for Ne⁵⁺. Left: excitation from the 2s²2p   ²P_1/2 ground level to the 2s²2p   ²P_3/2 level (1–2). Right: excitations amongst all 15 levels of the n = 2 configurations at the temperature (T_e = 4.0 × 10⁵ K) of peak fractional abundance in ionization equilibrium. The (red) “ × ” marks the 1–2 excitation shown in the lefthand panel. Double-horizontal lines correspond to agreement within 20%. Notes: the collision strength of Mitnik et al. (2001) is a scanned picture.