Lifetimes of the and states in 211At and their implication for effective charges and quadrupole moments

Abstract

The lifetimes of the 21 2 − state (1416 keV) and the 29 2 + state (2641 keV) in 211 At were measured to be τ m = 50.7(10) ns and τ m = 73.3(10) ns, respectively, using the γ-time technique. Using these lifetime measurements a value for the quadrupole moment of the 29 2 + state was derived. The explicit inclusion of octupole coupling effects into a description of the configuration for the 29 2 + level allows the extraction of an orbital independent effective charge of e eff = 1.5 e . From this a nominal value for the quadrupole moment of the π i 13/2 orbital can be deduced. New levels identified have allowed a determination of the strength of the π i 13/2 − π f 7/2 residual interaction.