Investigations of Ra$^+$ properties to test possibilities of new optical frequency standards

TL;DR

This study evaluates the potential of Ra$^+$ ions for optical frequency standards by calculating atomic properties that influence clock stability and accuracy.

Contribution

It provides detailed theoretical calculations of lifetimes, hyperfine interactions, and polarizabilities of Ra$^+$ states, supporting its suitability for atomic clock applications.

Findings

Long-lived metastable states suitable for clocks

Hyperfine interactions favorable for stability

Polarizability data supports optical trapping

Abstract

The present work tests the suitability of the narrow transitions $7s \ ^2S_{1/2} \to 6d ^2D_{3/2}$ and $7s ^2S_{1/2} \to 6d ^2D_{5/2}$ in Ra$^+$ for optical frequency standard studies. Our calculations of the lifetimes of the metastable $6d$ states using the relativistic coupled-cluster theory suggest that they are sufficiently long for Ra$^+$ to be considered as a potential candidate for an atomic clock. This is further corroborated by our studies of the hyperfine interactions, dipole and quadrupole polarizabilities and quadrupole moments of the appropriate states of this system.