Isolated core excitation of high-orbital-quantum-number Rydberg states of ytterbium

Abstract

We study isolated core excitation of ultracold ytterbium Rydberg atoms of high orbital angular momentum quantum number $\ensuremath{\ell}$. Measurements were performed on the $6{s}_{1/2}40\ensuremath{\ell}\ensuremath{\rightarrow}6{p}_{1/2}40\ensuremath{\ell}$ transition with $\ensuremath{\ell}=5--9$. The extracted energy shifts and autoionization rates are in good agreement with a model based on independent electrons, taking interactions into account in a perturbative approach. We reveal a slow decrease in the autoionization rates with $\ensuremath{\ell}$, explained by the strong coupling of the $6{p}_{1/2}n\ensuremath{\ell}$ autoionizing state with the $5{d}_{3/2}\ensuremath{\epsilon}{\ensuremath{\ell}}^{\ensuremath{'}}$ continua compared to previously studied divalent atoms.