Chapter 4 - ROTATION AND VIBRATIONS OF NUCLEI

Abstract

This chapter discusses the rotation and vibrations of nuclei. It also discusses the states associated with the excitation of collective degrees of freedom of nuclei. The shell model of the nucleus is based on the simplifying assumption that the individual nucleons move independently, the interaction among them being described by a self-consistent field. Because nuclear matter is characterized by low compressibility, the collective motion of the nucleons in nuclei reduces principally to deformations of the shapes of the nuclei, with no change in their volume. In the case of spherical nuclei, the collective excitations correspond to vibrations of the surface of the nucleus about the equilibrium shape. In nonspherical nuclei, the collective excitations can be associated with vibrations of the surface of the nucleus and with rotation of the nucleus in space. The chapter also explains that the rigid nonaxial rotator model, in which the interaction between the deformations of the nuclear shape and the rotation of the nucleus is neglected, is a fairly crude approximation to the real picture of the collective excitations in nuclei.