The excitation of Fe XVII by electron impacts

The cross-sections for the excitation of Fe XVII are computed using the Coulomb-Born approximation. For the excitation of the configurations 2p⁵ 3s, 2p⁵ 3p and 2p⁵ 3d, the intermediate coupling scheme is used, while an extrapolation is made for the excitation of the 2s 2p⁶ 3s, 2s 2p⁶ 3p and 2s 2p⁶ 3d configurations from the results obtained earlier in the lithium-like ions. It is found that the excitation cross-section Q (2p^{6 1}S₀2p⁵ 3p ¹S₀) is fairly large and partly removes the disagreement between the theoretical and experimental intensity-line ratios.Work supported in part by the Advanced Research Projects Agency (Project DEFENDER) monitored by the U.S. Army Research Office, Durham, N.C., under Contract DA-31 -124-ARD-D-139.Research Associate at J.I.L.A., Boulder, Colo., for the year 1965–1966.NASA-ESRO fellowship at the University of Colorado, Boulder, for the year 1965–1966.