SIMBAD references

Electron-impact excitation cross sections for Fe⁷⁺ are calculated using R-matrix close-coupling theory. The calculation includes 33 LS terms of the seven configurations: 3p⁶3d, 3p⁵3d², 3p⁵3d4s, 3p⁶4s, 3p⁶4p, 3p⁶4d, and 3p⁶4f. Following an intermediate-coupling frame transformation of the LS K-matrices, cross sections and effective collision strengths are obtained for 2926 transitions among 77 LSJ levels of the original seven configurations. After the solution of the corresponding collisional-radiative equations, the emission line ratio involving a blend of the 3p⁶4f ²F -> 3p⁶3d ²D transitions at around 131 A and another blend of the 3p⁵3d^{2 2}P -> 3p⁶3d ²D and 3p⁵3d^{2 2}D -> 3p⁶3d ²D transitions at around 168 A is found to provide a very useful electron-temperature diagnostic.