Energies and hyperfine splittings of the 7D levels of atomic francium -: art. no. 052507

We report optical double-resonance spectroscopy to locate and study the 7D(3/2) and 7D(5/2) levels of a sample of Fr-210 atoms confined and cooled in a magneto-optical trap. The upper state of the 7P(3/2) trapping transition serves as the resonant intermediate level to reach the 7D states. The energy difference to the ground state is measured for the accessible levels. We measure the hyperfine splittings: Delta>(*) over bar * (7D(3/2,)F = 15/2 <----> 13/2) = 167 +/- 4 MHz, Delta>(*) over bar * (7D(5/2),F = 17/2 <----> 15/2) = - 117.5 +/- 2.5 MHz, and Delta>(*) over bar * (7D(5/2),F = 15/2 <----> 13/2) = - 121 +/- 4 MHZ. Extrapolating the energies of the inaccessible hyperfine levels from the hyperfine constants and assuming B(7D(3/2)) = 0, the center-of-gravity energy difference to the ground state is E(7D(3/2)) = 24 244.831 +/-0.003 cm(-1) and E(7D(5/2)) = 24 333.298+/-0.003 cm(-1).