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arXiv · 1909.10581

High-precision measurement and ab initio calculation of the $(6s^26p^2)\,^3\!P_0 \rightarrow \, ^3\!P_2$ electric quadrupole transition amplitude in $^{208}$Pb

Daniel L. Maser·Eli Hoenig·B. -Y. Wang·P. M. Rupasinghe·S. G. Porsev·M. S. Safronova·P. K. Majumder
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Abstract

We have completed a measurement of the $(6s^26p^2)\, ^3\!P_0 \rightarrow \, ^3\!P_2$ 939 nm electric quadrupole ($E2$) transition amplitude in atomic lead. Using a Faraday rotation spectroscopy technique and a sensitive polarimeter, we have measured this very weak $E2$ transition for the first time, and determined its amplitude to be $\langle ^3\!P_2 || Q || ^3\!P_0 \rangle$ = 8.91(9) a.u.. We also present an ab initio theoretical calculation of this matrix element, which agrees with experiment at the 0.5\% level. We heat a quartz vapor cell containing $^{208}$Pb to between 800 and 940 $^{\circ}$C, apply a $\sim \! 10 \, {\rm G}$ longitudinal magnetic field, and use polarization modulation/lock-in detection to measure optical rotation amplitudes of order 1 mrad with noise near 1 $μ$rad. We compare the Faraday rotation amplitude of the $E2$ transition to that of the $^3\!P_0 -\, ^3\!P_1$ 1279 nm magnetic dipole ($M1$) transition under identical sample conditions.

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Daniel L. Maser, Eli Hoenig, B. -Y. Wang, P. M. Rupasinghe, S. G. Porsev, M. S. Safronova, P. K. Majumder. 2019-10-23. High-precision measurement and ab initio calculation of the $(6s^26p^2)\,^3\!P_0 \rightarrow \, ^3\!P_2$ electric quadrupole transition amplitude in $^{208}$Pb. https://doi.org/10.1103/physreva.100.052506

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