  Magneto-optically trapped atoms enable the determination of lifetimes of
metastable states and higher lying excited states like the
$\rm{5d^{2}~^{3}F_{2}}$ state in barium. The state is efficiently populated by
driving strong transitions from metastable states within the cooling cycle of
the barium MOT. The lifetime is inferred from the increase of MOT fluorescence
after the transfer of up to $30\,\%$ of the trapped atoms to this state. The
radiative decay of the $\rm{5d^{2}~^{3}F_{2}}$ state cascades to the cooling
cycle of the MOT with a probability of $96.0(7)\,\%$ corresponding to a trap
loss of $4.0(7)\,\%$ and its lifetime is determined to $\rm{160(10)~\mu s}$.
This is in good agreement with the theoretically calculated lifetime of
$\rm{190~\mu s}$ [J. Phys. B, {\bf 40}, 227 (2007)]. The determined loss of
$4.0(7)\,\%$ from the cooling cycle is compared with the theoretically
calculated branching ratios. This measurement extends the efficacy of trapped
atoms to measure lifetimes of higher, long-lived states and validate the atomic
structure calculations of heavy multi-electron systems.
