Combining experiments and relativistic theory for establishing accurate radiative quantities in atoms: the lifetime of the ${}^2$P${}_{3/2}$ state in ${}^{40}$Ca${}^{+}$

Abstract

We report a precise determination of the lifetime of the (4p)${}^2$P${}_{3/2}$ state of ${}^{40}$Ca${}^{+}$, $\ddot{I}{„}_{{\text{P}}_{3/2}}=6.639(42)$ ns, using a combination of measurements of the induced light shift and scattering rate on a single trapped ion. Good agreement with the result of a recent high-level theoretical calculation, $6.69(6)$ ns [Safronova et al., PRA 83, 012503 (2011)], but a 6-$\ddot{I}ƒ$ discrepancy with the most precise previous experimental value, $6.924(19)$ ns [Jin et al., PRL 70, 3213 (1993)] is found. To corroborate the consistency and accuracy of the new measurements, relativistically corrected ratios of reduced-dipole-matrix elements are used to directly compare our result with a recent result for the P${}_{1/2}$ state, yielding a good agreement. The application of the present method to precise determinations of radiative quantities of molecular systems is discussed.