High Rydberg Resonances in Dielectronic Recombination of P b 79

Dielectronic recombination resonances of $\text{Pb}\text{ }{\text{ }}^{79+}$ associated with $2{s}_{1/2}\ensuremath{\rightarrow}2{p}_{1/2}$ excitations were measured at the heavy-ion storage ring ESR at GSI. The fine structure of the energetically lowest resonance manifold $\text{Pb}\text{ }{\text{ }}^{78+}(1{s}^{2}2{p}_{1/2}20{l}_{j})$ at around 18 eV could partially be resolved, and rate coefficients on an absolute scale were obtained. A comparison of the experimental data with results of a fully relativistic theoretical approach shows that high-angular-momentum components up to $j=31/2$ significantly contribute to the total resonance strength demonstrating the necessity to revise the widespread notion of negligible high-angular-momentum contributions at least for very highly charged ions.