HIGHER-ORDER CRANKING CALCULATION IN THE INTERACTING BOSON MODEL AND INTERACTING BOSON-FERMION MODEL

Considering that the IBM and IBFM cranking calculations in lowest order of angular frequency give reasonably good estimates for the moment of inertia, we extend them to study the dependence of the moment of inertia on higher order terms. We find that an analytic expression for the correction terms can be derived. Numerical calculations for Gd-154 and 161Er are performed and compared with experiment. The Hamiltonian is taken from a microscopic approach. Calculated results show that the properties of higher-order terms depend on the deformation of the rotating system, but the correction yields only a limited effect when omega is small.