Electron-impact excitation of Xe ²⁶⁺ and its resultant spectral signature

We have carried out a 129 close-coupling level Dirac-Coulomb R-matrix calculation for the electron-impact excitation of Ni-like Xe. We have utilized this data to generate the spectral signature of Xe26+ in terms of feature photon-emissivity coefficients (F-PεCs). We have compared these F-PεCs with those generated using semi-relativistic plane-wave Born excitation data, which forms the heavy species baseline for the Atomic Data and Analysis Structure (ADAS), We find that the Born-based F-PεCs give a reasonable qualitative description of the spectral signature but that, quantitatively, the R-matrix-based F-PεCs differ by up to a factor of 2. The spectral signature of heavy species is key to diagnosing hot plasmas such as will be found in the International Thermonuclear Experimental Reactor.