Rotational excitation of a spinless deformed nucleus via time-independent perturbation theory
Excitation levels are useful tools to deduce the shape of a nucleus. In the simple collective model, one can treat a deformed nucleus as a rigid rotor that rotates about its body-fixed axis. Excitation level of highly deformed nucleus follows the usual pattern expected from the discretized angular momentum. In this study, we treat the rotation as a perturbation to the ground state level of an already deformed nucleus. By exploiting the orthogonality of spherical harmonics, we found that the nuclear rotation cannot be treated perturbatively. The resulting correction to the ground state level far exceeds the level spacing of the expected rotational levels.