Isotope shifts for ${}^1S_0-{}^3P_{0,1}^o$ Yb lines from multi-configuration Dirac-Hartree-Fock calculations

Abstract

Relativistic multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations with configuration interaction (CI) are carried out for the $^{1}S_{0}$ and $^{3}P_{0,1}^o$ states in neutral ytterbium by use of the available GRASP2018 package. From the resultant atomic state functions and the RIS4 extension, we evaluate the mass and field shift parameters for the $^{1}S_{0}-\,^{3}P_{0}^o$ (clock) and $^{1}S_{0}-\,^{3}P_{1}^o$ (intercombination) lines. We present improved estimates of the nuclear charge parameters, $\lambda^{A,A'}$, and differences in mean-square charge radii, $\delta\langle r^2\rangle^{A,A'}$, and examine the second-order hyperfine interaction for the $^{3}P_{0,1}^o$ states. Isotope shifts for the clock transition have been estimated by three largely independent means from which we predict the unknown clock line frequencies in bosonic Yb isotopes. Knowledge of these line frequencies has implications for King plot nonlinearity tests and the search for beyond Standard-Model signatures.