Measurement of the lifetimes of the lowestP13state of neutral Ba and Ra

Abstract

The lifetimes of the lowest $^{3}P_{1}$ states of Ba and Ra were determined to be $1345\ifmmode\pm\else\textpm\fi{}14\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ and $422\ifmmode\pm\else\textpm\fi{}20\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$, respectively, by measuring the exponential decay of fluorescence after illuminating a thermal atomic beam with pulses of laser light. In addition, the $^{1}S_{0}(F=1∕2)\text{\ensuremath{-}}^{3}P_{1}(F=3∕2)$ transition frequency in $^{225}\mathrm{Ra}$ was measured to be $13\phantom{\rule{0.2em}{0ex}}999.269\ifmmode\pm\else\textpm\fi{}0.001\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ by referencing a nearby ${\mathrm{I}}_{2}$ transition.