The O(6) description of the nuclear rotation

A recently developed algebraic version of the collective model has shown that a full range of Bohr model calculations can be executed in bases that range continuously from those of a spherical vibrator to a beta-vibrational Wilets-Jean limit. Thus, the establishment of close relationships between the algebraic structure of this model and the IBM is of special importance because one can learn from the complementary perspectives they afford. In this paper, we show by calculations that the familiar rotor-gamma vibrational spectra of the Bohr model can be obtained in the IBM by the addition of a scalar cubic in the quadrupole moment operators, of the type considered recently by Van Isacker, to an O(6) Hamiltonian. Simple fits of the low-lying spectra, electromagnetic transition rates and moments of inertia of the ground and gamma bands of¹⁶²Dy and¹⁶⁸Er are presented.