Electron impact excitation of helium-like neon

We report on Breit–Pauli R-matrix calculations of collision strengths for Ne IX, including all levels up to n = 4. Here, we study the effects of relativistic spin–orbit coupling, radiation damping of resonances and convergence of partial wave expansions. The results are substantially more accurate than previous studies, and resolve discrepancies that brought about uncertainties in spectral diagnostics. This work is carried out as part of the Iron Project-RmaX Network.