The results of ab initio calculations of electric-dipole amplitudes, lifetimes, and polarizabilities for several low-lying levels of ytterbium are reported. The effective Hamiltonian for two valence electrons H eff was constructed by means of the many-body perturbation theory and solutions of the two-electron equation H eff ⌽ n ϭE n ⌽ n were found.

To support efforts on cooling and trapping of alkaline-earth atoms and designs of atomic clocks, we performed ab initio relativistic many-body calculations of electric-dipole transition amplitudes between low-lying states of Mg, Ca, and Sr. In particular, we report amplitudes, and for 3 P o 2 → 1 D 2 transitions. For Ca, the reduced matrix element 4s4p 1 P o 1 ||D||4s 2 1 S 0 is in a good agreement with a high-precision experimental value deduced from photoassociation spectroscopy [Zinner et al., Phys. Rev. Lett. 85, 2292 ]. An estimated uncertainty of the calculated lifetime of the 3s3p 1 P o 1 state of Mg is a factor of three smaller than that of the most accurate experiment. Calculated binding energies reproduce experimental values within 0.1-0.2%.

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We calculate energies and hyperfine structure constants A and B for low-lying levels of 173 Yb. The latter is treated as a two-electron atom. To account for valence-valence correlations the configuration interaction method is used. Valence-core correlations are accounted for within the many-body perturbation theory which is used to construct effective two-electron operators in the valence space.