1 Calculations of parity nonconserving s - d transitions in Cs , Fr , Ba + , and Ra +

We have performed ab initio mixed-states and sum-overstates calculations of parity nonconserving (PNC) electric dipole (E1) transition amplitudes between s-d electron states of Cs, Fr, Ba + , and Ra +. For the lower states of these atoms we have also calculated energies, E1 transition amplitudes, and lifetimes. We have shown that PNC E1 transition amplitudes between s-d states can be calculated to high accuracy. Contrary to the Cs 6s-7s transition , in these transitions there are no strong cancelations between different terms in the sum-overstates approach. In fact, there is one dominating term which deviates from the sum by less than 20%. This term corresponds to an s-p 1/2 weak matrix element, which can be calculated to better than 1%, and a p 1/2-d 3/2 E1 transition amplitude, which can be measured. Also, the s-d amplitudes are about four times larger than the corresponding s-s transitions. We have shown that by using a hybrid mixed-states/sum-overstates approach the accuracy of the calculations of PNC s-d amplitudes could compete with that of Cs 6s-7s if p 1/2-d 3/2 E1 amplitudes are measured to high accuracy.