An equations-of-motion method for anharmonic vibrations: Application to a degenerate shell model

An equations-of-motion method is proposed for calculating anharmonic effects in doubly even spherical nuclei. The method can be viewed as an extension of the QRPA theory for spherical nuclei, and its applicability is demonstrated for the case of a degenerate shell model of configuration ($\text{21}\text{2}$)⁶ by comparison with the results of a previous exact diagonalization.