Radiative decay of triply excited 2p2np4,2S° states to the 1s2pmp4,2Pstates in lithiumlike ions

The Rayleigh-Ritz variational method is used with a multiconfiguration-interaction function to obtain the nonrelativistic energies and wave functions of the triply excited 2${\mathit{p}}^2$np ${}_{}{}^4{}_{}{}^{}$S° (n=2,3,4) and 2${\mathit{p}}^2$3p ${}_{}{}^2{}_{}{}^{}$S° states and also the doubly excited 1s2pmp ${}_{}{}^4{}_{}{}^{}$P (m=2,3,4), 1s2${\mathit{p}}^2$ ${}_{}{}^2{}_{}{}^{}$P, [(1s2p${)}^3$P,3p${]}^2$P, and [(1s2p${)}^1$P,3p${]}^2$P states for atomic systems with nuclear charges from Z=3 to 10. The relativistic and mass polarization corrections are evaluated via first-order perturbation theory, and the resulting relativistically corrected energies are used to compute transition wavelengths for 2${\mathit{p}}^2$np ${}_{}{}^{4,2}{}_{}{}^{}$S°→1s2pmp ${}_{}{}^{4,2}{}_{}{}^{}$P. The fine structure of the 1s2pnp ${}_{}{}^{4,2}{}_{}{}^{}$P states is also calculated with first-order perturbation theory. The nonrelativistic wave functions are used to compute the electric-dipole transition probabilities for 2${\mathit{p}}^2$np ${}_{}{}^{4,2}{}_{}{}^{}$S°→1s2pmp ${}_{}{}^{4,2}{}_{}{}^{}$P; this information is then used to compute the lifetimes for the 2${\mathit{p}}^2$np ${}_{}{}^{4,2}{}_{}{}^{}$S° states and the branching ratios for the transitions to the 1s2pmp ${}_{}{}^{4,2}{}_{}{}^{}$P levels. Intermediate-coupling effects for the 2${\mathit{p}}^3$ ${}_{}{}^4{}_{}{}^{}$S°${,}^2$D°${,}^2$P° and the 1s2${\mathit{p}}^2$ ${}_{}{}^4{}_{}{}^{}$P${,}^2$D${,}^2$P${,}^2$S states are investigated for the case of Z=10 and are shown to be small. Comparisons with experimental wavelength and lifetime measurements are made.