The observed levels of the configuration 3d 4f of Fe VII are compared with theoretical formulas which include the electrostatic interaction and the spin-orbit interaction. The least-squares calculation gives a mean error of 79 cm-1 and permits a critical discussion of the reliability of the experimental levels.
YEHUDA SHADMI, "Configuration 3d 4f in the Seventh Spectrum of Iron," J. Opt. Soc. Am. 56, 647-647 (1966)