Triaxial rotor model description ofE2properties inOs186,188,190,192

Abstract

The triaxial rotor model with independent inertia and electric quadrupole tensors is applied to the description of the extensive set of $E2$ matrix elements available for $^{186,188,190,192}\mathrm{Os}$. Most large and medium transition $E2$ matrix elements can be reproduced to within $~10%,$ and most diagonal elements to within $~30%$. Most small transition matrix elements can be reproduced to within $~30%,$ and they support the interference effect exhibited by the model between the inertia and $E2$ tensors: this is a new feature of quantum rotor models. The diagonal $E2$ matrix elements at higher spins in the $K=2$ band are extremely sensitive to admixtures of higher $K$ values: the low experimental values in $^{190,192}\mathrm{Os}$ indicate significant admixtures of $K=4$ components. Attention is given to the ${K}^{\ensuremath{\pi}}={4}^{+}$ bands in these nuclei and the controversial issue of whether they are of quadrupole or hexadecapole nature.