Abstract
We present lifetime measurements of the and levels of Fr. We use a time-correlated single-photon counting technique on a cold sample of atoms in a magneto-optic trap. We excite the atoms with the trapping and repumping beams of the magneto-optic trap and detect the decay of the atomic fluorescence. The results are a precision experimental test of the atomic many-body perturbation theory applied to the heaviest alkali metal. The lifetime results are 21.02(11) ns and 29.45(11) ns for the and levels, respectively. This gives a line strength ratio / of 0.526(3) for these levels in Fr. To study sources of systematic errors we measure the lifetimes of and in stable and obtain 26.20(9) ns and 27.64(4) ns, respectively.
- Received 29 September 1997
DOI:https://doi.org/10.1103/PhysRevA.57.2448
©1998 American Physical Society