Higher-Order Terms in the Variable Moment-of-Inertia Model

The variable-moment-of-inertia model for the ground-state rotational bands in even-even nuclei has been extended by adding an anharmonic term to the potential energy. A detailed application of this model, called VMI23, has been made to the ground-state bands of 122 even-even nuclei. It is shown that the inclusion of the anharmonic term improves agreement with the experimental data in many cases, and provides a sensitive means of probing the potential energy surfaces of nuclei.