Alkali-metal negative ions. IV. Multichannel calculations ofK−photodetachment

The results of ab initio calculations of photodetachment of ${\mathrm{K}}^{\mathrm{-}}$ are presented and compared with experimental measurements. The energy region studied is from threshold to the vicinity of the first excited state of neutral potassium. The calculations are essentially nonrelativistic in nature, but the fine structure in the first excited state (a doublet) is resolved in the calculations by a three-step process: a transformation of dynamical variables to a form that is relatively independent of energy over an energy range comparable to the splitting, an algebraic transformation from LS to jj coupling, and finally by kinematic corrections for the splitting. The initial transformation, a simple phase rotation, was determined empirically, but is shown to be consistent with a formal correction for the effects of long-range polarization forces in electron scattering by potassium near the 4p ${\mathrm{}}^2$ $P^o$ threshold.