Oscillator strengths for the magnesium isoelectronic sequence

The relativistic random-phase approximation is used to calculate the excitation energies and absorption oscillator strengths for the $3s^2{}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}-3s3p{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$, -$3s4p{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$, -$3s5p{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$, and -$3s3p{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ transitions of selected elements of the magnesium isoelectronic sequence through nuclear charge $Z=92\mathrm{}$. The results are compared with previous theoretical and experimental values. The data plotted as a function of $Z^{-1\mathrm{}}$ enable us to study deviations from the predictions of the nonrelativistic $Z$-expansion theory.