Electric quadrupole moment of the Rn211 632- isomer: Absence of core deformation at very high spins

The electric quadrupole moments of Rn211 isomers were determined as Q(172-)=19(2) e.fm2 and Q(632-)=160(22) e.fm2 via measurements of the quadrupole interaction in a Bi single-crystal host. The results indicate that the spherical shape is preserved in the lead region even at the core-excited very-high-spin regime, in contradiction to theoretical predictions.