Orthogonalized operators are introduced in the atomic configurations ƒN in order to yield parameters that are more precisely defined and more stable than the conventional ones. Of the four Racah operators e0, e1, e2, and e3, only e1 needs adjusting. The set of two-electron scalars is made complete by the generalized Trees operators eα′, eβ′, and e υ′. Of the three-electron scalars ti, only t2 requires alteration. The theory is illustrated for ƒ3 by adding the orthogonalized operators in successive steps and comparing the fits with those obtained if the conventional operators are used.
© 1984 Optical Society of America
B. R. Judd and H. Crosswhite, "Orthogonalized operators for the ƒ shell," J. Opt. Soc. Am. B 1, 255-260 (1984)