Here are the abstracts of some of the publications from the Stony Brook group relevant for francium.
Magneto-Optic Trapping of Radioactive 79Rb
G. Gwinner, J. A. Behr, S. B. Cahn, A. Ghosh, L. A. Orozco, G. D. Sprouse, and F. Xu
Physical Review Letters 72, 3795 (1994)
Radioactive 79Rb atoms have been produced in a nuclear reaction and were captured into a magneto-optic trap in a cell. A fluorescence signal was obtained from 80 79Rb atoms in the trap. The efficiency of the process from production to trapping is estimated as 1 10-5. This efficiency is sufficient to develop further experiments to measure atomic properties of Fr with the eventual goal of observing parity non-conservation effects in neutral atoms of different radioactive isotopes of Fr.
Magneto-Optic Trapping of 210Fr
J. E. Simsarian, A. Ghosh, G. Gwinner, L. A. Orozco, G. D. Sprouse, and P. A. Voytas
Physical Review Letters 76, 3522 (1996)
The alkali element francium has no stable isotopes and has eluded extensive study because sufficient quantities have not been available for detailed investigations. More than 1000 210Fr atoms have now been contained in a magneto-optic trap. This number is sufficient to allow extensive studies of Fr atomic properties that are necessary input for future tests of fundamental interactions. The 210Fr (T1/2 = 3.2 min) were created in the nuclear reaction 197Au (18O,5n)210Fr and were extracted from the target and injected into the trap. The ratio of the trap loading rate to the production rate in the target was 10-4, which is 50 times larger than in previous experiments with 79Rb.
7S1/2 9S1/2 Two-Photon Spectroscopy of Trapped Francium.
J. E. Simsarian, W. Shi, L. A. Orozco, G. D. Sprouse, W. Z. Zhao.
Optics Letters 21, 1939 (1996)
We report the spectroscopic measurement of the 210Fr 9S1/2 energy performed using two-photon excitation of atoms confined and cooled in a magneto-optic trap. The resonant intermediate level 7P3/2 is the upper state of the trapping transition. We have measured the energy difference between the 9S1/2 state and the 7S1/2 ground state to be 25671.021 0.006 cm-1.
Measurement of the 7p 2P3/2 State Lifetime in Atomic Francium
W. Z. Zhao, J. E. Simsarian, L. A. Orozco, W. Shi, and G. D. Sprouse
Accepted in Physical Review Letters (Scheduled for June 2, 1997)
We present the first measurement of an atomic radiative lifetime in Fr. We use a time-correlated single photon counting technique with a cold sample of 210Fr atoms in a magneto-optic trap. The results are a precision experimental test of the atomic many-body perturbation theory applied to the heaviest alkali. The lifetime for the 7p 2P3/2 state of 21.02(16) ns gives a value for the reduced transition matrix element between the states 7s 2S1/2- 7p 2P3/2 of 5.898(22) a0 atomic units.