In atomic systems for which the total oscillator strength of excitations from the ground state is dominated by the transition to the lowest resonance level, the f -sum rule provides a bracketing inequality connecting the lifetime τ of that level to the dipole polarizability α d . This relationship has been used previously to deduce α d from τ . It is shown here that improved spectroscopic accuracies now permit this procedure to be inverted, with τ deduced from a value for α d obtained spectroscopically using the core polarization model. A similar quantitative relationship exists connecting the nonadiabatic correlation factor β to τ , and thus also to α d . The method is applied to a recent measurement of α d for Kr 6+ to obtain the values τ (4s4p 1 P 1 ) = 0.096 ± 0.003 ns and β(Kr 6+ ) = 1.71 ± 0.03a 5 0 . It is shown that the use of this method to make precision lifetime determinations for a small number of ions in an isoelectronic sequence permits the exploitation of observed semiempirical regularities to specify the lifetimes of all ions in that sequence.