Blackbody radiation shift, multipole polarizabilities, oscillator strengths, lifetimes, hyperfine constants, and excitation energies in Ca+

TL;DR

This paper presents a comprehensive high-precision relativistic study of Ca+ atomic properties, including polarizabilities, oscillator strengths, lifetimes, hyperfine constants, and BBR shifts, with improved accuracy and detailed uncertainty estimates.

Contribution

It introduces advanced methods for accurately calculating highly-excited state contributions, significantly improving the precision of polarizability and BBR shift values in Ca+.

Findings

Improved static polarizability value for 3d_{5/2} state by a factor of 3.

Calculated BBR shift of the 4s - 3d_{5/2} transition as 0.381(4) Hz at 300K.

Provided recommended atomic property values with uncertainty estimates for Ca+.

Abstract

A systematic study of Ca+ atomic properties is carried out using high-precision relativistic all-order method where all single, double, and partial triple excitations of the Dirac-Fock wave functions are included to all orders of perturbation theory. Reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined for the levels up to n = 7. Recommended values and estimates of their uncertainties are provided for a large number of electric-dipole transitions. Electric-dipole scalar polarizabilities for the 5s, 6s, 7s, 8s, 4p, 5p, 3d, and 4d states and tensor polarizabilities for the 4p, 5p, 3d, and 4d states in Ca+ are calculated. Methods are developed to accurately treat the contributions from highly-excited states, resulting in significant (factor of 3) improvement in accuracy of the 3d_{5/2} static polarizability value, 31.8(3) a.u., in comparison with the previous calculation [Arora et al., Phys. Rev. A 76, 064501 (2007)]. The blackbody radiation (BBR) shift of the 4s - 3d_{5/2} clock transition in Ca+ is calculated to be 0.381(4) Hz at room temperature, T=300K. Electric-quadrupole 4s -nd and electric-octupole 4s -nf matrix elements are calculated to obtain the ground state multipole E2 and E3 static polarizabilities. The hyperfine constants A are determined for the low-lying levels up to n = 7. The quadratic Stark effect on hyperfine structure levels of 43Ca+ ground state is investigated. These calculations provide recommended values critically evaluated for their accuracy for a number of Ca+ atomic properties for use in planning and analysis of various experiments as well as theoretical modeling.