Nuclear Models and the Osmium Isotopes

The energies of, and transition probabilities involving, the ground-state rotation bands of ${\mathrm{Os}}^{186}$, ${\mathrm{Os}}^{188}$, and ${\mathrm{Os}}^{190}$ are compared with a diagonalized rotation-vibration theory in which vibrations are considered to three phonon order. Agreement even in the Os transition region is found to be excellent. The theory appears to be particularly successful in predicting two phonon states in ${\mathrm{Os}}^{190}$.