The fine-structure splitting between the 3p<sup>6</sup>3d <sup>2</sup>D<sub>J</sub>, J = 3/2 and J = 5/2 levels of K-like ions, Ti<sup>3+</sup> to U<sup>73+</sup>, are calculated by means of Dirac–Fock single-configuration and multiconfiguration wave functions. The multiconfiguration calculation includes jj configurations arising from some selected nonrelativistic configurations in the M-shell Coulomb complex; these include all the Dirac-Fock configurations with the principal quantum number n = 3, which are degenerate in the pure jj coupling limit for infinite nuclear charge Z, along with other configurations such that the calculated energy is correct to order Z<sup>2</sup> and Z asymptotically. The difference between known experimental and calculated multiconfiguration Dirac–Fock fine-structure splittings is almost independent of Z, thus allowing us to predict unknown values reliably. From this plot and a comparison of theoretical and experimental results we conclude thatthe observed fine-structure splitting of Ag<sup>28+</sup> [J. Opt. Soc. Am. B 2, 1661 (1985)] is too small. We present splittings in high-Z K-like ions for which experimental values are unknown.
© 1992 Optical Society of America
M. A. Ali and Y.-K. Kim, "Improved calculation of fine-structure splittings in the ground state of potassiumlike ions," J. Opt. Soc. Am. B 9, 185-190 (1992)