RELATIVISTIC MANY-BODY CALCULATIONS OF TRANSITION RATES FOR CA+, SR+, AND BA+

Relativistic many-body theory is applied to determine amplitudes for 4p --> 4s, 4p --> 3d, and 3d --> 4s transitions in Ca+; 5p --> 5s, 5p --> 4d, and 4d --> 5s transitions in Sr+; and 6p --> 6s, 6p --> 5d, and 5d --> 6s transitions in Ba+. The calculations, which are carried out through third order in perturbation theory, give lifetimes for excited p states that agree with measured values to better than 10%. The agreement improves to the 2% level after semiempirical corrections are included. The lifetimes predicted for the metastable 4d3/2 and 4d5/2 states in Sr+ and for the 5d5/2 state in Ba+ also agree well with measurement, but the theoretical lifetime of the 5d3/2 state in Ba+ is a factor of 4 larger than the measured lifetime.