Radiative transition probabilities of the1s2p2P2and1s2p2D2states of the lithium isoelectronic sequence

A $Z$-expansion procedure is used to obtain eigenvalues and eigenfunctions for the $1s^{2}2p{}_{}{}^2{}_{}{}^{}P_{}^o{}_{}{}^{}$, $1s2p^2{}_{}{}^2{}_{}{}^{}P$, and $1s2p^2{}_{}{}^2{}_{}{}^{}D$ states of the lithium sequence. Expansions in inverse powers of the nuclear charge $Z$ are obtained also for the dipole-matrix elements and oscillator strengths of the $1s^{2}2p{}_{}{}^2{}_{}{}^{}P_{}^o{}_{}{}^{}-1s2\mathrm{}{p}^2{}_{}{}^2{}_{}{}^{}P$ and $1s^{2}2p{}_{}{}^2{}_{}{}^{}P_{}^o{}_{}{}^{}=1s2\mathrm{}{p}^2{}_{}{}^2{}_{}{}^{}D$ transitions, valid for $Z>\mathrm{}3\mathrm{}$. A separate calculation was performed for lithium. The calculated transition probabilities agree with the Hartree-Fock values of Gabriel for large $Z$, but there are considerable discrepancies with the experimental data.