Low Terms in Co VII and Ni VIII

The levels $3d^3 {}_{}{}^4{}_{}{}^{}FP {}_{}{}^2{}_{}{}^{}G\mathrm{DH}$ (and ${}_{}{}^2{}_{}{}^{}P$?) and $3d^{2}4p\left({}_{}{}^3{}_{}{}^{}F\right) {}_{}{}^{42}{}_{}{}^{}G\mathrm{FD} \left({}_{}{}^3{}_{}{}^{}P\right) {}_{}{}^4{}_{}{}^{}D\mathrm{PS} \left({}_{}{}^1{}_{}{}^{}G\right) {}_{}{}^2{}_{}{}^{}HG$ have been identified in Co VII and Ni VIII. The graphs of relative energy against $Z$ for the even levels are, on the whole, smooth; however ${}_{}{}^2{}_{}{}^{}G{}_{}{}^2{}_{}{}^{}H{}_{}{}^2{}_{}{}^{}D$ show marked and very similar irregularities, which remain unexplained. The doublet separations behave in a regular fashion. The sharp decline in certain of the odd levels, especially ${}_{}{}^4{}_{}{}^{}F\mathrm{DDP}$, between Co VII and Ni VIII can be explained as due to the approach of (undiscovered) levels of the $3p^{5}4d^4$ configuration, which are expected to cross $3d^{2}4p$ near this stage of ionization.